Talking about experience, I'm studying at Oxford at the moment on and integrated course. I would recommend their ground school to anyone.
They publish their own course material, and are constantly updating according to changes in JAA rules etc.
In their books they have a great amount of feedback questions (Questions that people remembered after taking the JAA exams and fed them back to the instructors). This definately helps to get through the JAA's!
They use a lot of computer aided animations which helped me understanding some concepts a little bit easier.
If you want do study long distance you can actually get some cd-roms that will help you understand more about one of the 14 subjects.
The instructors are very professional and the accomodation (if you want to study on site as opposed to long-distance) is good (all air conditioned)
But by all means, do your own investigation. Most of these ground schools have a seminar that you can go to.
Hope this helps
C-T