Lots and lots to do, lots and lots to discover. Different enough to not be "more of the same", but similar enough to not feel everything is alien. Not just another UO, but still UO. Development is constant, multiple bugfixes and features added daily, largely based on user input. good stuff.
I also played MUDs btw so there might be less generational gap than you might think! we just added more "ultima online" to the game, which some might say doesn't keep true to the original ultima games.