Definitely. I don't know of any forum software that can handle 500+ users with one server. Unless maybe they are doing some major caching
stratics.com runs a two server config because they routinely have 500-600 users online. It's just the nature of the beast. In order to keep up with everything, queries, page rendering, etc. it takes alot of overhead.
And you're right again that more features adds more queries. That's one of the hard things is to balance features that really improve the software against the extra overhead needed for them.
Anywho, everyone's got their favorites which is why I never comment on other forum software becuase honestly I don't know anything about them. Not like I'd have the time to even if I wanted
You're getting the bugs because we're currently in the middle of a beta release and fixing them out as they are spotted. Thanks for pointing out the ones you encountered.