has horrible code, is not easy to administer, not great at moderation either and an insult to any power user. But I understand that most people enjoy the style and have their own definition of efficiency.
has invalid HTML and for power users the AJAX all over is not that efficient either. Notifications and watch lists can't be filtered or configured. The search is slightly better than phpBB
's, as it has not the bug to interpret search operators in search phrases
. The philosophy of relying on paid code that you have to re-buy from time to time is something I'll never understand if you want to have your BBS for a long time.
's code is not the best, but compared to others much better, even when not fully OO. The administration is good and makes sense once you understand the permission system. Moderation can be done quite easily and there's little you miss from the start. For power users the style needs some minor tweaks, but even then the default outsmarts all other BBSs - it's just the outlook that seems to scare most people off (although saying what means "nice" to them is still a challenge