Pretty stable, in terms of game- or quest-breaking crashes. It's also getting better about random crashes too. The keybindings referenced above are seriously worthwhile. There have been one or two reports of world states not importing correctly. I may or may not have had that problem. The reason I'm unsure is that there is a possibility that I was importing the state for a different character without realizing it - I didn't double check first, so it might have been user error for me.
I've got a playthrough with every specialty and every romance option, except I haven't tried reaver. Others say it's a lot of fun. Combat is great fun but a little quirky. The AI pathfinding is pretty awful, so if a character has to move somewhere it's better to take direct control. Being able to switch between tactical and isometric camera mode helps a lot. There is a slight bug where sometimes during combat, either the controlled character or companion will freeze in place. If that happens, switch to direct control and jump in place. That breaks the lock on their movement or attacks.
They're doing small updates all the time, and the large patches have fixed everything major anyway.