Best from the lot

I took the GMAT CLUB TESTS when I exhausted all the resources I was referring to. No kidding, the variety of questions is amazing!
You will get to know where you stand, your weak points and your strong points as well. THERE IS A SEPARATE COLUMN OF MUST BE TRUE QUESTIONS AS WELL!!! I haven't seen that anywhere else.
The trick in the questions will keep you on your toes. Even the most basic questions will urge you to bite your nails off!!

If you are planning to break that plateau of 700, I will definitely advice you to go for these tests. Not only you will get used to hard questions but also get accustomed to the time management, which is very crucial for a gmat test taker.