If you're thinking about the 10-day program, please consider this, based on my experience teaching such courses for PIC...
First, the training is incredibly intense. Most of my students say they were surprised by the level of intensity -- 8-9 hours a day, 10 days in a row, plus a couple of hours of homework every night. If you do this on vacation, make sure you're off work for 14 days, because you'll probably need the other four days at the end to recover before going back to work.
Second, that which is quickly learned is as quickly forgotten unless as quickly exercised. In order to "fix" the newly/quickly learned material in your brain, you must fly one or two IFR hops a week for four to six weeks starting immediately after the practical test. If you don't, within a month, you'll be as though you never took the course (well, not quite that bad, but you certainly won't be ready to launch solo into the IFR system in real IMC).
Third, you'd better be proficient in the plane in which you will take your training. No trading your 172 on a Bonanza two weeks before the IR course, getting five hours transition training from your local CFI, and expecting the IR course to go well. This is especially true for lower-time pilots with no experience in anything but the simple trainer in which they got their 50 XC PIC who then bought something heavy and/or complicated and/or really different, and immediately try to get their IR in it. If you only fly 30 hours a year, and they're the same 30 hours year after year, you probably need a quick proficiency cram course (a commercial pilot flight maneuvers program would be about right) prior to the IR course.
Fourth, you must be academically prepared. If your only IR ground training before the 10-day course is one of those 2-day written test cram courses, you won't know anything but the answers to the written test, and you will not be able to finish the IR flight course in ten days -- figure two to four days extra to learn all the material that would otherwise be learned in a real IR ground training course. I recommend any or all of the following, choice based on your own learning style (and whether or not you can sit still for Martha King):
· Formal IR ground school of 40 hours or so classroom plus home assignments (like those offered by many flight schools and community colleges)
· Self-paced computer based training course like Jeppesen's FliteSchool
· DVD course like King or others
· Book learning, using a good training manual like Bob Gardner's Complete Advanced Pilot or Bill Kersher's Instrument Flight Manual, and/or the FAA Instrument Flight Handbook and FAA Instrument Procedures Handbook
In addition, you should study the following books:
· Current FAR/AIM (especially the ASA version with the list of recommended FAR's and AIM sections for IR/CFII)
· FAA AC 00-6A Aviation Weather
· FAA AC 00-45F Aviation Weather Products
Finally, you must dedicate yourself entirely to the program. Don't just turn off your Blackberry -- leave it in the office. Explain to your family that this isn't a vacation, this isn't even work -- they can't expect you to participate in anything other than your training for the duration. Forget about catching up on your reading (other than IR training books) or email or internet chat. You will eat, sleep, and breathe instrument flying for 10 days, and if you clutter your mind with, or spend your time on, anything else, it won't happen on schedule.
With this preparation, you will find a program like PIC's productive and useful. You'll get real IR training, including sim training (which is highly useful in making the flight time more productive -- teach on the ground, practice in the plane), from a highly experienced instructor (PIC's average 8000 hours) with real-world IFR experience, and you will be well-prepared for actual IFR operations. You will also experience real IFR flying in real IFR weather -- something I consider invaluable, and something your local time-building CFI with no significant real IFR experience may not be comfortable doing. Without this preparation, you'll just end up tired and frustrated – and your instructor will, too, because s/he wants you to succeed just as much as you do.