Well, just so happens I am studying for IR written test right now, and have bought BOTH the Sporty’s online school and the King School for IR, so I can tell you my impression of both.
TLDR:
Sporty’s probably OK to pass the test , but left some gaps in my knowledge from a practical / flying standpoint. After completing the Sporty’s course I bought King school to get more test-prep before my exam. King is dated but has more of a “
sitting down for a long chat with an experienced pilot” kind of feel to it. If you want a good mobile app to take videos and practice tests on-the-go then definitely go with Sporty's.
Full story:
I started with Sporty’s because I used Sporty’s for my PPL. I like the modern videos, the presentation and graphics are nice. They have a very good iOS app also, that allows all videos to be viewed offline, and practice tests to be studied while on-the-go. I went through the whole video series, took several practice tests, and got my endorsement to go take the written exam. However, I still felt there were gaps in my knowledge.
My experience back from my PPL test was that a few questions at the FAA exam were never addressed in Sporty’s videos or practice test materials (and I took a lot of practice tests). But hey I passed PPL fine even though I was blindsided by some topic areas I'd never seen from Sporty's
Back to the IR: but I felt there were alot of questions I still had about IR operations that I felt I was not getting from Sporty’s, so I paid for the IR course from King School to make sure I was completely prepared before going into this exam. Also I travel often, so being able to access the course from a mobile device was important to me (either a web browser on a internet-connected tablet/laptop, or a native mobile app) so I could study even while on travel.
I then bought the King School becuase I wanted more before I did the test. The King school has videos that are obviously dated, but others are updated as necessary. Some of the older low enroute charts they show still had the shaded areas for Class G airspace, with class E only around 10nm of the Airways; you don’t see that anymore in-fact it’s hard to find any “Class G up to 14500 ft” areas anymore. Most of the videos are from VHS days , they intersplice some updates to correct material but it is jarring cut-in that interrupts the video. Other videos are all re-done, sometime in the ~2015 timeframe. Most recent video updates are about GPS (including WAAS), but it’s obvious that a majority of their videos are from before the GPS era. However, in areas where the fundamentals of IFR flying haven’t changed in 20 years, they are probably just fine.
The software presentation is modern and very nice on Sporty's, basic but functional on King School. They both run in a web browser and runs fine on my computers (both Linux , Windows, and even from an Android tablet device via Chrome browser).
Sporty's has a very nice iOS app that has almost 100% of the functionality of the entire course built-in to the App. Can take practice tests in the app, also.
King School has a basic iOS app, but it’s limited. For me in the IR courses I bought (I have the "get it all" package) the King iOS app shows a collection of various videos, you have to select the correct ones to sync-up with your lesson plan on the computer. There a knowledge quiz at the end of some videos or some lessons. But, As far as I can tell, there is no way to take any practice tests or just practice exam questions using their app, it seems to be for viewing their videos only.
So in the category of presentation and mobile app, the advantages definitely goes to Sporty’s.
Comparing the knowledge I’m getting from both courses, it’s hard to make an apples-to-apples comparison becuase for Sporty’s I just bought the IFR package and they only have that one; but on King I bought a much more extensive “get it all” package for IFR flying. This is more than just the ground school it also has several video series on real world IFR flying help, like single-pilot ops and risk management, more info on weather, how to handle emergencies, etc. keep in mind I paid about double the cost to get this whole package from King vs the class from Sporty’s.
but outside of just studying for the IR exam i _think_ I get more out of the course as a practical matter: it’s like John and Martha King saying “we’ve done all this IFR flying and here’s what we are telling you from our experience”. I feel like there is more real-world anecdotes thrown in of “here’s what the test will ask you, but also here’s how its really is going to happen when you fly”
Example1:you do an instrument approach to a non-towered airport, that has magenta ring for Class E airspace at 700ft AGL. You have to fly to LPV minimums (200 AGL) due to weather, but Once you get below 700 ft are you in class G uncontrolled airspace? If you are still in IMC from 700ft down to Minimums, Are you still guaranteed traffic separation during the last part of your approach to minimums ? Sporty’s never explains this, but King did.
Example2: the practice test in Sporty’s have questions about using an
RMI and ask to determine your our position based on the indicator needles. But Sporty’s never explained an RMI or how to read it, I had to guess my way through the test. Martha King did explain the RMI. yeah I know an RMI is outdated and never seen one in a plane, but if it’s on the FAA test don’t leave me hanging.
Side note: I did try a demo for Shepherd Air, but their software is horible to use. Instead of just running in a web browser, from any computer anywhere (like Sporty's and King), the Shepard Air requires a Windows application to be installed on your computer, and its very outdated. I hated working with it, and decided not to buy after that demo.
Haven't tried Gleim recently, but back in my PPL I tried Gliem and it was hard to work with their software. They require Adobe Flash, which is mostly obsolete and makes it very hard to take the class "from any computer anywhere" and blocks you from accessing it from a mobile device, so I didn't buy Gleim course just based on that.