i am pretty sure you will like it,
i like the java server myself is quite powerful and expandable into multiple physical hardware for load
the C# client needs a little bit of love, since it is running a dated version of the axiom rendering engine,
but after all is a direct X 9 so graphics quality can get as good as any other direct X 9 engine outhere is just matter of creating the right shaders for it.
give it a go, dont let the sampleworld demo deceive you, this is because the assets used in it are way outdated aswell as the textures,
i found out that by adding my own art work and materials textures it will look as good as any other good game engine.
feel free to post in the forums if you need help getting started..
one other great feature about multiverse is the wiki, is very well documented and lots of great tutorials to learn from.