I find that the search button is pretty good. Just put in a search for the bike model you want info on, and you'll usually get a couple threads that comprise of
30% people who own the bike and their experiences
20% people who have seen the bike online or in person and have an opinion on it
30% people who own a similar bike and give you their opinion on that particular model
20% random comments
1 guy who hasn't ridden your bike but considers it equivalent to a unicycle and will start explaining the strengths and weaknesses of your bike based on his experience with a unicycle
All in all, pretty useful info. Google is really useful as well. Keep an eye on the model's year as well as they sometimes make fairly drastic changes and a review that was relevant one year may not be relevant the next.
Good luck