I can't stand the OG 12th
edition. The questions are insanely easy compared to the real gmat. I really don't think that book (when used exclusively) will get you anything higher than a 600.
You are right, my friend.
OGs give us only a glimpse about the GMAT.
We need harder questions.
You've gotta go with the Manhattan GMAT
stuff imo, thought I haven't looked at any other books closely. I am incredibly impressed with the MGMAT guides
, they are well thought out, organized, and they teach you the theory behind the most difficult questions rather than cookbooking a recipe that will only work for some problems. They have helped me immensely in the past month or so with my studying.