I guess the class is ok if you learn better in a classroom setting but most of those classes, they just regurgitate whatever the book says anyway. (according to my girlfriend and college roommate who are in law school right now who both went with a Kaplan course). If you have a good teacher, they might have a little extra input/advice.
Haven't taken the LSATs but I've taken the GRE's which is from what I heard similar with the logic problems and stuff. Standardized testing in general is just learning the tricks and using the knowledge you have. I think a book and lots of practice problems will do you just fine.