Reply to thread

Both. Based on my experience, though it has been quite some time since I've looked at ipb (I do own a copy).

For your specific requirements, as suggested in the other thread, other forum software could be a better choice than ipb/xf. There is a lot not being discussed such as 'which' old browser (mentioned in other thread). IE6 does not do well with xf compared to IE8, but Firefox 2.0 is as fast (or faster) on xf compared to firefox 3.6.13..

If you are concerned about the speed of your server but do not care about being in search engine results then you could keep the search bots out.

Overall I would say there is no way to make any comparison at all, except to have the people you want as members try it out. Either on xf.com & ips.com, or in a demo. I've no idea what is entailed in getting a demo at ips.com, but it is automated and quick here: http://xenforo.com/demo