I used to recommend that site, but no longer advise it because the owner and moderators are pretty much out of control, in my very humble opinion:
1) It not only accepts advertising, it appears the owner will edit posts of anyone who potentially could be an advertiser; then demand advertising money to allow the person to answer critics. The many ads don't seem to be enough, though, since the owner also asks for donations. (Check out the skeptical posts in
http://www.vansairforce.com/community/showthread.php?t=73748 and
http://www.vansairforce.com/community/showthread.php?t=74247 and what happens when Jan E. tries to respond.) According to a post in the Yahoo Viking engines list, the owner wanted $3500 before he would let Jan E. make "promotional" posts. (Oddly, the same criteria was not applied to a thread about the Jabiru for the RV-12.)
2) The volunteer moderators lock and delete threads without thinking too deeply about how it makes them look. I recall one thread started by a moderator who is also a DAR wherein he announced he would no longer inspect RV-12s because Van's Aircraft wasn't giving him some technical information he felt he needed to check some aspect. Eventually it was pointed out to him by some posters that the information was in a document supplied to every RV-12 builder. The DAR/moderator then deleted the entire thread. As I recall, only when someone started another thread asking what happened to the thread did the DAR/moderator state what he had done.
3) Too many moderators:
http://www.vansairforce.net/rules.htm#moderators
4) Too one-sided: Full control of threads and even editing of posts with no consequences. Ad revenue plus donations from users plus moderators who work for free equals one sweet deal.