Blueprint for sure. I took it with them and they were great. The instructors really cared about our progress and would always stay after class to answer questions or help us with certain things. Also, not only did they know the LSAT inside and out, the instructors were really cool people. They would make class really fun. On top of that, all of the people that work in the office were so nice and always helpful. You really can't go wrong with Blueprint. I know people that took both Blueprint and Testmasters and all of them say Blueprint was by far much better. As for Kaplan and those other ones that I don't even know their name, their methods are just bland and mundane, those guys should stick to SAT prep because the LSAT is a whole other species. So anyway, good luck with what ever you choose!
The best advice I could give you is this. Try self studying first. Buy some prep tests and the powerscore bibles. See if you can learn on your own. If you are having problems, then take the class.
F*cking bi+ch drinks a 1 oz bottle of goose and thinks she's French