I've had Descent for a bit over a year now. We play it as a break from D&D every once in awhile. With the large selection of heroes and the skill cards it plays different each time (plus the scenarios which we have yet to repeat one).
We have all taken turns as the Overlord and find that it is equal fun to be the overlord or one of the heroes. With four players, we usually have the overlord and three heroes. When there are only three of us to play, the two players each play two heroes. Playing with only two heroes is pretty much a death sentence for the heroes unless you do everything right.
We're pretty heavy into the game having painted all the monsters and heroes and I made 3D pieces for the tiles with Hirst Arts molds.
I haven't had the chance to play Talisman so I can't comment on a comparison.