When Xenforo was first released I wasn't all that keen on it myself however since it's been released I have found that the more I was a member on forums that used Xenforo the more it grew on me. I myself moved my forum over to Xenforo in January of this year from vBulletin and I must admit it is the best thing I have ever done myself. I love working with it and I love how much you can do with it aswell.
It's an impressive software and very powerful. I personally like the alerts and inbox systems; but the alerts are probably my favorite. I love how you can be notified very easily if someone replied to your post, quoted your post, liked your post - ect.
I like the look of Xenforo and having used it before as an admin would recommend it, assuming you have money for the license. Though really it's just under $20 a month when you figure it out by the month. Not a bad investment considering many forums earn more than that. You just have to decide if a paid forum software offers you more than what you'd get with free software. And, certainly Xenforo does.
XenForo is one of my favorite online board softwares, as it is coded with jquery and as a nice modern look along with advanced features. In addition this software is really cheap, unlike invision power board. IPB is still my top board software, but it is way to expensive and the license has be extended every 6 month for a huge amount of money.
It is a great software indeed. In the past I was not really interested in it as it seemed very weird compared to IPB or vBulletin. Considering I had been using vBulletin for many many years, the change was a little weird.
But I do enjoy Xenforo very much, it has some great features. But I still have to put it behind both vBulletin and IPB. I just like the features of vBulletin and design of IPB to be a lot better than Xenforo. Xenforo in my opinion seems very childish and unprofessional like. I would never actually use it myself.