I could care less which one turns out to be better, since I'll be getting both (unless one happens to delete your OS - but what do I know, I bought POR2).
What DOES matter, though, is which one I'll be picking to make my mod, which I'm preplanning for now.
In terms of toolset, it seems like DA will be more powerful, whereas NWN2 will be more accessible. It all amounts to how this balances out - how more powerful will NWN2 be than NWN, or harder (or even, easier, if Obs managed to pull it off) will it be to use? How easy will DA's terrain system be to use to render NWN2's tilesets obsolete? How much better will NWN2's tilesets be compared to NWN? Now, mind you, I'm not programmer, but I did manage to be able to use NWN's toolset for basic tasks (well, basic enough to make use of the more important aspects for me - dialogue and story). I didn't use mindblowing or overly complex scripts or anything. All in all, it'll depend on how the power and accessibility will balance out between the two toolsets.
Also, it'll also depend on how good the henchman system for NWN2 will work. Personally, I'd prefer party control, but on the other hand, having henchmen would mean that you would only directly control YOUR character (so that everything that happens in the game happens in YOUR character's viewpoint - so party members can't be used to initiate convos with randoms). Also, henchies would be a good excuse to implement more convos in battle. Give order, write up lots of possible responses for the individual NPC in a particular situation, and make it original. I'd probably be writing more in-combat dialogue whenever something storywise affects the battle if I had henchmen rather than controllable party members. I know you can give dialogue to your party members, but it feels kind of awkward when you give an order to yourself and respond to yourself.
In terms of MP gaming, NWN2 will probably win by default, as I suspect the DM client will be most powerful. DA says it'll include something similar, but it remains to be seen how much it will actually offer.
In any case, I'll have to play through both and assess, and try both their toolsets.
DA's system seems intriguing, though we don't know enough about it. I love BG2's battles. On the other hand, 3.5e is also pretty cool.
Either way, I would have preferred a toolset/DM-based TB online game. That would have made for very cool MP sessions.
TB