I just completed my CPL and CFI within the last 2 months.This was my experience (tl;dr, you've been warned. Stop here or dont complain, your choice):
CPL - King School for ground.
My CPL license was a long drawn out affair. I "officially" decided to go for my CPL in January 2017 but did not complete it until February 2019. Weather in the spring of 2017 was less than favorable followed by a job assignment that was less flexible regarding hours and in an area without access to a reliable complex aircraft continually delayed my efforts through most of 2017. Buying a house in early-2018 and a job loss right after closing on the house in mid-2018 both delayed further efforts as I first tried to show stable finances without extravagant spending through the first half of the year and then entered into financial conservation mode through the 2nd half of the year.
I finally got serious about completing my commercial license in mid-January and started flying towards the rating again in early February.
I found the King Ground school to be slightly-to-moderately helpful. The course was largely a recap of already possessed knowledge but it did cover a few new things, mainly regulations related to commercial operations (what you are and more importantly, are not allowed to do as a commercial pilot... i.e. holding out), the new maneuvers and a few other topics (for example I dont recall seeing V-g charts in my PPL).
It also helped with the new terminology (such as Chart Supplements vs A/FD, Non-Towered Field vs Uncontrolled Field, 60-days vs 2-calendar months on practical test readiness/flight training endorsement), the FAA has decided to foist upon the aviation community in what seems to largely be an effort to justify their existence/budget instead of providing other services (such as airmen services and checkrides or certifying new aircraft such as the 737 Max, yeah I went there). These changes were less critical for the purpose of the CPL but were very important during my CFI checkride as the DPE wanted to hear me using and teaching with the updated terminology.
Flight-wise I spent 9.2 hours in February-April of 2017. 4 Flights with an instructor totaling 4.3 hours between February 11 and March 11 and then 4 flights and 4.9 hours solo between March 18 and April 18. Though I flew another dozen or so hours over 7 or 8 flights in 2017, most of these were "mission oriented" flights without a lot of maneuvering and I didn't fly again specifically for my Commercial until February 2018 (lack of access to a complex which was still a requirement of the commercial exam at that time was the primary culprit). I logged 1.1 hours in February 2018 solo and another 1.3 hours in April 2018 with an instructor before flying less than 5 hours through the remainder of 2018 (including a VFR flight review) and January 2019.
When I finally decided to get serious in Mid-to-late January, I spent a week and a half going through the King Ground school from scratch, 2 days of which were spent entirely on written test prep (to get the King ground school issued endorsement for the written you need to take and pass 3 sample exams, I did one per day in an effort to avoid artificially inflating my score due to question familiarity). I did an IPC on February 2 and then proceeded to log 7 flights and 8.0 hours between February 3 and February 19 in preparation for the checkride, 7.1 hours of which were with an instructor.
All told, I logged 19.6 hours and 17 flights in preparation for my CPL with 12.7 hours with an instructor. Truth be told, if I had been more consistent with my flight times it probably would have taken me a third less flights and flight time a I definitely could have cut out at least the 2 flights in 2018 and probably reduced the number of flights in 2019 from 7 down to 3 or 4 and 4 hours but I was not consistent.
I took and passed my CPL checkride February 22 which was 4 weeks to the day from when I reached out to my local flight school and recommitted to doing my CPL. I would not consider this a "compressed" or "accelerated" CPL course but I did come into it with all my prerequisite XC flights and other times already fulfilled and a more than passing familiarity with the new maneuvers and how they were performed so we were able to focus all of our attention on the checkride and associated maneuvers.
Checkride was 1.2 hours on the ground and 1.2 hours in the air.
CFI - No Ground School
Unlike my PPL/IRA/CPL, it is the only license to date that I did not use a ground school program for. Frankly, I dont know that I see the need for a ground school like King or Sporty's unless you are looking for a comprehensive review program and even then you might not need it. My IRA and CPL courses were both King Schools online and I had upgraded my King School's PC PPL to the online edition somewhere along the way too; I didnt really use them but I imagine if I needed that comprehensive review, they would have worked just as well as purchasing CFI material. There really shouldn't be a whole lot of "new" information and most of the ground work is really spent working on lesson plans and figuring out how to teach the material.
For me there were a few things I forgot (mostly things that aren't common in GA like swept wings, leading edge flaps, etc and some of the less functional equations [i.e. lift equation]) and the only thing really "new" was Fundamentals of Instruction and better understanding of the "common student errors." For FOI, I just read the Aviation Instructor's Handbook and used ShepphardAir ($45) for test prep as many of the questions on FOI have more than 1 correct answer and you need to select the "best" answer, which often came verbatim from the text and for "common student errors" you can pretty much just refer to the ACS for the test/maneuver in question and look at what the failure criteria is to get an idea of what errors look like as well as the maneuver in the Airplane Flying Handbook which tells you the common errors.
That being said, between the SheppardAir tests and the roughly 1 hour spent going over each chapter of the Pilot's Handbook of Aeronautical Knowledge book 1-on-1 with an instructor as well as 1 hour on FOI topics (18-20 hours total ground), I spent about $50 more than I would have buying the King "Get-It-All" Flight Instructor package and $300 more than the King "Cessna Cleared for Instructing" Part-141 package. Though I'd argue you'd still need time 1-on-1 with an instructor even with the King schools program... That "let me play the dumb, know-nothing student and have you teach me" interaction is invaluable in my opinion.
Flight time, I did a 2.3 hour flight familiarizing myself with flying from the right seat and covering PPL manuevers, 1.4 hours covering CPL maneuvers and Take-offs/landings, another 1.1 focused on polishing PPL and CPL maneuvers and takeoffs/landings and 1.6 hours on a mock checkride all with an instructor. So a total of 4 flights and 6.4 hours with an instructor and an additional single flight with 1.2 hours solo.
I also decided to redo my spin endorsement as I had an opportunity to fly a Citabria and didn't want to pass it up and my spin endorsement was done in 2015 which I didn't consider to be "recent" (my DPE liked this and commented on what some people have tried to pass off as recent). I spent 1.5 hours on my Spin Endorsement in addition to the 4/6.4 spend on maneuvers.
My checkride was almost 9 hours total. We did 4.6 hours on the oral which was close to 6 hours with breaks and the administrative portion (signing IACRA, inputing ID and test results, etc). We then went up flying for 1.4 hours which was close to 2 hours including pre-flight and post-flight operations and ended in a disapproval on the last maneuver of the flight test; after a total of 10 hours, 1 hour to the airport, 1 hour flying to the DPE and 8 hours testing, I was a bit brainfried and excited knowing I only had to take-off and land twice to get a pass and ended up both dropping it in and landing long on my shortfield landing which only ratcheted up my anxiety before doing a shortfield takeoff during which I got ahead of myself and uttered the words "accelerate in ground effect to Vx" earning me a disapproval.
My disapproval was more due to a slip-up then a deficient knowledge or skill so I did a short ground session and 1.1 hours flying with an instructor doing "remedial" work on my "deficiencies" during which we simply covered the fact that I knew exactly what I did wrong and how to avoid it again. I then went back to the DPE and we spent 0.6 flying the pattern 3 times and 0.4 doing the administrative work of issuing my certificate bringing my total exam time up to 9 hours.
My time spent working on my CFI-A was about 4 weeks during which I did 20 hours of ground, 10.2 hours of dual, 6 hours of solo (most of it getting to/from the DPE), 6 hours of checkride oral, 2 hours of check ride airwork and 2 hours of checkride administrative work and an hour tabulating my log book and doing IACRA for a total of 48 hours. I again would not consider this an "accelerated" CFI-A course. Accelerated courses seem to cover both CFI and CFII in the time it took me to cover just CFI; some even include MEI if you are already multi-engine rated. The longest day was probably about 3-4 hours at most and consisted of a 2 hour ground session, a 1 hour flight and maybe an hour doing pre/post-flight debrief. My average day was closer to 2 hours whereas accelerated courses seem to do full 8 hour days. That being said, I did spend 2 hours a day, 4-5 days a week at the airport and I had already taken the 2 written exams (FIA & FOI; I also did AGI) before my first lesson with my instructor and I had already started on my lesson plans so there wasn't a lot of time spent drafting them, though I did some minor updates and revisions as I went through the material to match my style and to address some of the things I missed or had to move around having placed them in other lessons that the instructor brought up while doing the ground sessions.
Truth be told I probably would have been better off doing a more accelerated course as I spent nearly as much time commuting to and from the airport 45 minutes each way over the 4 weeks/17 days as I did in training but instructor, plane and DPE availability all played a part in extending it out as it did.