Great Practice

I tried the MGMAT CATS twice(as in take all their 6 tests at different stages in my GMAT journey). They are the next best thing after the OG and GMAC tests.
The first time my goal was to get a 650 and I was always struggling with verbal. MGMAT helped me increase my quant from low 40s to mid 40s but I did not see any improvement in the verbal section. My CAT scores were in the 550 - 620 range. I was not heavily impressed. Almost after a year, I made some major changes to my GMAT strategy, studied obsessively and came back to MGMAT. To my surprise, the MGMAT CATs were very accurate. They are on par with the GMAC/GMAT Prep CATS.
I was told that MGMAT is slightly more difficult than the GMAT Prep tests. I didn't think so. The Quant questions will prepare you for a high 40s/low50 score. The verbal - I have to disagree with some of their SC questions - they don't adhere to GMAT grammar concepts 100% of the time.
I think if anyone takes this material seriously, the time spent is worthwhile.