Well, remember I haven't played since '99 and haven't been involved with any of our guilds in other games.
One of the things that really caused UO to lose it's appeal to me was the creation of the trammel/feluca patch. It took away the edge of having to watch my back at all times because when playing in Trammel all I had to worry about was the monsters, not monsters and people. At the same time it seemed like everyone you met in feluca just wanted to fight, which while cool wasn't very interesting because everytime I ran into someone they'd just want to fight. I played DAOC a little bit too, and it had the same type of thing, if you see someone from another realm you knew they were hostile. No options to make friends, infiltrate, negotiate, build relationships with etc...
But my question was not necessarily a guild wide good/evil thing. But whether a character could be good/evil/inbetween on an individual basis. Those people who ran with me a lot... WCoast, Brightblade, Scout Finch, Lags, Alodar know that we got ourselves into and out of a lot of sticky situations catching known thieves and pk's. It was a ton of fun because we never know how they are going to react, unlike monsters where you know they will attack, and unlike players from a different realm, where you know they will attack.