Well the bugginess it had was because of gamebryo but there weren't a TON of bugs that really affected you in any way. I think there was only one bug that actually kept you from going on with your game (Clavicus Vile quest). People need to realize that there are bugs in every game, no matter how hard you try to make them bug free.
Yeah i'm not too sure we can completely blame gamebryo for the bugs, it does seem that all of Beth's games ever since Daggerfall have suffered similar issues. The most popular bug being falling through the floor but general clipping is pretty popular too. Like you said though all games have bugs and I couldn't care less about them. I've never quit a game because of bugs.
I worked as a software tester once and one of my team mates was obsessed by them, he would actually not buy a game if he feared it would be buggy. I felt sorry for him.