Green_Grass - 8:13 am on May 7, 2010 (gmt 0)
It seems to be a very subjective decision. If you are getting continuous low QS ( from manual reviews) and have some one to correspond with at Google LPQ team, request them for some advice. Make the request polite and they MAY give some hints as to what you need to change. ( this is not in the realm of fantasy, because I have got specific advice in the past as to why I am getting low QS,.. Remove adsense from pages.. etc ..)
I have also noticed that a general advice / (unique) article kind of a website with affilate links kind of blended in..seem to be o.k. If there is too much advertising or too many affilaite links with poor site navigation ( squeeze pages), you will Fail the manual review.
You also need to be careful that you do not keep re submitting low QS pages for review, because then you may be BANNED. So be careful.