I scored 660 in april 2010 (without using manhattan material) and gotten a god-awful verbal score of 33. After the 660 debacle, I bought the manhattan verbal series, went through the manhattan material in about a week and gave 4 out of the 6 MGMAT tests (740,740,710,750). Didn't do the remaining 2 as I became lazy :P
Today, I gave gmat again and this time got 740 :) M-49,V-41. All I can say is that Manhattan rocks and the MGMATs are spot on! Honestly, gmat-prep from gmac doesn't even come close to MGMAT.
Just wanted to thank the manhattan team. I used only manhattan forums for seeking explanations to the questions that I didnt understand/got wrong. Also, the instructors had given really simple explanations! I learnt a lot from them (without even interacting with them :) )
Big Thank you Manhattan!