I really got a lot out of the Gleim Co. computerized at home study system. You do it at your own pace, and I remembered a lot of the material by going over it more thoroughly. You review an outline of important stuff, and then use the PC based program to practice. After a while you can get real good at it. A number of my students used the same system and really liked it.
I used it for my commercial, instrument, and ATP. It was not available back then for the FE written, so I used the King product - which I did not like nearly as well.
I had a lot of ATP students that had taken the all ATP quickie test prep, and most of them couldn't recall a lot of the material that was needed for the oral.
I went to Bill Phelps in Phoenix for both. See my post under the ALL ATP Bad Experience thread. I got much more out of going to class than I ever did studying at home. I studied for most of my pre-ATP writtens at home and went to class for Instrument and II.
I would opine that it all depends on your learning style. No matter how motivated you may be, it is hard to sit down at home and study. It is easy to find excuses not to study, especially after working all day. With class, you are fully immersed in the subject. You also benefit from the interaction between teacher and class.