As Brogan stated, nobody other than you can take the decision.Everyone will have different considerations, and we do not know everything that makes you tick. The reason I used the wording I did was mostly because I thought some of the comments made earlier were a little over the top. Yes, of course there is a chance that Kier gets hit by a bus.
But if that is how you reason, you would be worrying all the time. Fact is that when it comes to that kind of stuff, you just cannot possibly influence it. In that way, you "will have to take a risk".
XenForo might only be a year old, but you yourself mentioned the momentum it already has gained is strong. The reason for that is simply that it's fantastic software.
I invested in vBulletin and several modifications to it. In total, 3 suite licenses, 2 vBGallery licenses, 1 vBSEO license, Classifieds license, a skin, and various other paid or donated mods. I did not have to think long about whether I wanted to get an XF license or not. Heck, I think I bought 2 or 3 the first day they were available. Yes, of course there was the risk of the lawsuit, but I already got bitten by vB with their pre-sale event, and on XF I at least had the software in my hands straight away.
Judging by how things are going over at vB, I would say you probably would be off safer with XenForo. The fact it's a joy to work with is then an added bonus 
I did not mean any disrespect with my previous post, by the way. I just thought the thread was getting quite ridiculous with all the "what ifs" and "perhaps this-es".
