You will never beat the nwn1 experience, ive played all the mmo's and still not found anything.
I enjoyed EQ2, GW, WoW, D&DOnline, LotRO and im now enjoying AoC.
But i could never spend enough time on these mmo's (with the exception of GW) to get to end game (or even high lvl instances as PUGs are generally bad and people quit to easily) so i never really felt like i was getting anywhere.
NWN PW's you feel like your doing something in the time you play and you have DM interacting to make it thrilling.
There are some good (if not great) NWN2 PW's out there and im hoping Dragon Age will be stunning. Also i think NWN2 got a lot better with MotB, not sure how the PW's used all the extras to their advantage.
Just find a mmo you like and stick with it till you get bored and go back to nwn

I like AoC because its new and everyone isnt leet.