I got a IPB license (the whole shabang with the suite and the CCS) and I was gonna convert one of my communities to it. But to be honest, I am not that impressed. Within a half hour of using it I discovered a bug in the Blog system (which I submitted) and the amount of addons/plugins is really nothing to write home about. Then there's no proper language files for German admins (vBulletin has official ones for all their products) and it's really a lot more trouble than it's worth. Then there's no Social Groups - and for the community of mine in question, that is a big deal. So yeah, I'm sticking with vB 3.8 for a while until vB4 becomes a proper product with enough add-ons and the code rewrite is completed. So now I'll be looking to sell my licenses. Not trying to talk IPB down - I'm sure there are thousands of people who love the software and it's right for them. For me it's vBulletin hands down.
May I ask which version you tried? Can you let me know what basic functionality you felt was missing? I'm genuinely interested to learn how we can improve our software. Did you feel that our own forum lacked community? Did you receive access to the customer forums?