I felt that the Kaplan QR was very close to the real thing. The hardest thing about studying for the QR test is to learn all the "tricks", and to have several of the word problems down cold to the point that you don't have to think about it. The good thing is that the types of word problems (average speed, people working in parallel, probability, etc) were very similar to the practice tests.
The key is to work on as many QR practice problems as possible, and practice learning how to solve them in 30 secs. Once you learn the "tricks", the math is much faster without a calculator.
Also, I felt that the DAT test provided on the ADA website was very close to the real thing.
I scored 21 on QR.