It's unlikely that the initial commercial version will support UltimateBet. At minimum we are supporting the top 6 sites according to PokerScout. If you purchase PT2 now, your $55 will go towards your PT3 purchase when it is released.
Since PT2 supports UB, I'm just curious why not include UB in the initial PT3 release? I imagine you have tons of HH. Of course, I'm biased since I play a lot of UB...