Don't get confused by the feedback you read on webmaster forums, where mostly enthusiasts participate. vBulletin is still (by far) and will continue being for the foreseeable future, the market leader. It's gonna take XenForo many years (if ever) to reach the sales levels and/or name recognition of vBulletin.
As much as I love vBulletin, I've used it for 8 years, I think XenForo is a superior product and I'll probably switch my main forum to it in the following months, but, being superior has nothing to do with sales. I think XenForo could be more of a competitor to IPB.