To me, this question is like asking whether you like movies/TV or books. They are different genres, with their own strengths and weaknesses.
Graphical MMOGs/MUDs are like movies. Very much focused on the "doing" rather than the "thinking". MUSHes/et al. are like books, heavy on the characterizations and introspection. And this difference is often why turning a book into a movie fails so badly. You can't take the 1st person aspects and the narrative into the 3rd person world of a movie easily.
For me, a novel can be as engrossing as a movie. It used to be that a movie could never duplicate the imagination, but that is less true these days. But given this, I've found I don't need the visual aspect of these games anymore. That's why I only play MUSHes now. I decided to not play Seed because I didn't want to spent any time in the mini-games of hatches or whatever. I want to leave those duties to "off-screen" activities that could be assumed my character was doing.
In the end, I want to play games that make me feel like I'm in an interactive book (or movie), not actually in a "game".