As rahulraao mentions... it does suck... use it only to improve certain aspects like timing etc... don't rely on their scores (I still dont understand how they score, I got 6 wrong in one Q for a 48 and 5 wrong in one Q for a 44??).
And yes, they never reply back inspite of a 24HR tutor guarantee!!! I'm still waiting for reply for the past 5 weeks.
Quant is ok.. some are directly out of the OG... though I found some typo's and blatant errors (one of the questions, DS, OA is A and the OE goes to explain why B is correct).
Verbal is ok... a lot is way too obvious ... unlike OG/PP.
I just took the quant tests to improve my timing and a couple of verbal till I gave up as it didnt help much.
As for others, PR is a good test resource (especially after they updated their question sets online), Kaplan has some tough Q but the V is not like the OG (also, Kaplan's scoring is confusing) and of course there is PP & GmatPrep - probably the best test preps (close to real) out there.