I prefer the boards with the most membership as they seem to be more active. Universalignited has around 70 members. IOACentral has a little over 3800 members. Screamscape doesn't have a discussion board. Universal-Excitement has around 1500 members. Universal-excitement has great pictures there but everytime that I click on the main page it tries to download something to my computer called "HOOK.wma" I don't know what that is but I don't like things downloading onto my computer without asking me for permission first. I have a Mac and so I'm not very worried about viruses but many downloads are made for windows and not for Mac. So any site that immediately downloads something onto my computer is one I stay away from. The Disboard has around 120,000 members but many do not contribute to the Universal forums.
If you aren't concerned about the discussion boards, then any of the sites mentioned above would be fine. They all have great information and pictures. If you are looking for discussion, go with the ones with the most people.