I used Barrons. I thought the questions were much harder than the real LSAT. It might have been that the Barrons grading scale was off though.
Either way, I did way better on the real LSAT and the one real practice LSAT I did. My guess is that they did this on purpose so everyone will show improvement on the real LSAT.
I thought the advice in Barrons was pretty good.
If I were taking the LSAT again, I would get as many real LSATs as possible and just keep taking them. I know there are at least two books of real LSATs linked from the books page