The MGMAT tests people are referring to are the full length CAT's offered online only. I believe one is free and for additional must be purchased (total 6 CAT's).

I've have found these CAT's to be more difficult especially in Quant. But the major benefit over all the others PR, Kaplan etc is that the MGMAT CAT's helps identify your weaknesses. The results of the CAT shows which level of questions your getting correct (e.g. avg correct SC 610 and avg incorrect SC 630). They are also closer to the actual compared to others (Kaplan, PR). I've frankly given all and found MGMAT the most useful.

I know where to focus. I'm giving my 3rd MGMAT CAT today.

P.S. I've also purchased Kaplan Q bank but find MGMAT much more useful.

i'm doing the MGMAT question - the free one online .. i'm jst wondering if it's the same difficult level as the purchased one .. any knows?

Yes, MGMAT is for ManhattanGMAT. That is what I come to know when I go through several posts in this forum.