1) Should you take prep classes?
The answer to that really is if you are are self motivated to study on your own. If you are, if you can devote the time to prepare yourself, I would think that ideally that's what you should do. Also, money is a big factor. If you have the money to spend on prep classes, I guess go for it. The biggest thing that the prep classes do is MAKE you study by having you go there.
2) What books to have?
I too was in the same boat. I *just* purchased the MGMAT set of 8 books. I tried reading all the blogs and I saw that a lot of them say that the Kaplan ones are a bit weak. I do not know that for a fact. However, if most are saying that, then no smoke without fire...
A lot of them recommend PowerScore Bible for CR, but that's your call. Reading financial editorials from WSJ or such seems to help a lot of people. Again, I am a newbie, haven't tried it. Just passing what I found...
Lastly, one of my very good friends gave me a great advise. The books only do so much. If millions of people are buying these books, they can't be all that bad. So just pick one, and start practicing. That's all.
Hope this helps. I am in a similar position. I have narrowed down the books, but I am trying to find help on "how to squeeze in time" and also "Q or V first?".
Good luck.
-uhsa