If you're talking about the free one they give out, then I'd say "yes, definitely harder than the real deal." If you take the course they offer, my understanding is that the tests start out hard and get progressively more like the actual test to make you feel like you're making progress (I don't know if all companies work like that, but I think they do.) I bombed the KAPLAN free-test so badly I didn't even bother to go get my scores from them , and when I took the actual test, I kicked a$$.
Don't let the test comapnies scare you too much.