I have been an IPB user since its free days (1.*) and vB user since v2. I've migrated all my forums to IPB by the time vB 3.6 came out. I simply liked IPS' direction and community features more than those of vBulletin. Mind you, I still like the direction they're taking IP community suite, but...
How good are CloudFlare's nameservers? Right now my sites use DynECT SMB, which is a geographically-distributed, load-balanced and fault-tolerant system.
All my sites adhere to class B no-www compliance, and I won't lose any sleep crying over any idiot visitors who get confused by the lack of www in my sites' URLs.
да это я так, зашел на сайт посмотреть, а там злоебучий вбуль стоит. по-моему, уж лучше было бы любой бесплатный движок поставить.
с другой стороны, конвертер на XF пока только с vB3.*