So I just took comlex II today, and completed most of comquest (>90%) as of yesterday. Just fyi - the % correct data's been updated.
I'm really glad I spent a lot of hours with comquest, bc today I felt like I was back at home doing more comquest questions. The interface of quest is the same exact interface you'll see on test date. The questions were very representative of the TYPE of comlex questions overall. I've done only 50 questions on Combank, which were very well written as well, but their interface was completely different than the NBOME's blinding white and blue screen. The usmleworld questions were too well written to be representative of comlex questions, and the legal questions are not as hard as the ones you'll see on comlex.
Having said that, I'd say 9 out of 10 questions on OBGYN today were nearly identical to the ones from comquest. The jurisprudence and cardio on comquest were RIGHT on, as well as OMM, GI, respiratory. It was actually kind of scary yet reassuring to see very familiar questions. I have to say half my test was OMM today - and even though quest has an awesome strategy for sacral diagnosis and explains cranial well, you really need to spend a good amount of quality time with savarese to pick up the minutia you'd expect from step 1. There were a lot of anatomy questions I didn't expect to see.
Overall, the explanations on quest are brief, concise, yet easy to read and cover most of what you need to know. They let you know what's been high yield, and their comments are actually rather accurate. Would definitely use them again.
Good luck!