I found the ground school pretty straight forward. Passed all of the exams first time around (sat 3 on one day in april and the remaining four on one day on June). The CATS in line stuff is OK, but not up to the standard of say OAT, but its good enough. You have an option of purchasing the manuals (I got given a set and they never got opened). The only thing I would recommend buy as an extra is the OAT Met CD.
The CATS question bank pretty accurately reflected the questions in the exam and were very useful in judging whether you had done enough prio to sitting an exam. The weekend groundschools were great value and very well presented by a knowledgeable tutor.
If you want it spoon fed then go somewhere else, if you have a bit of nouse and want some flexibility then I think CATS get about 9 out of 10.
Give Stuart a call and discuss the weekend bit - although it might seem obvious to us lot but when I went to see him to jack up the course for the 30 of us who started, it was clear that they had never really thought about IR studying for businessmen. they seem to have caught on now and made a tidy sum for a little additional weekend work - works for them works for us.
For weekend IR training I have found Wycombe Aic Centre excellent - started July and now 40 hours into it.