I'm not in any hurry at all to move away from UBB.Threads. I've spent so much time and money getting my site the way I want it, with the twenty-plus modifications, that it would be a HUGE headache to move to a new bb. I don't know if the new UBB would be PhotoPost compatible and FusionBB's galleries don't come close to what PP offers, so I have my hands tied really.
I still have over two years on my license and I'll take my time, just running Threads. I can make a decision on my next bb later, when both FusionBB and the new UBB are on their way towards version 2.0 or so.