I've heard some tube amps that have sounded awful and I have heard some solid state amps that sound great. Some of the solid state amps today are so good I don't think most people could tell the difference sound wise.
The problem with solid state for me is the feel and response. You don't have the sponginess of a tube amp. The whole system you are playing through changes with solid state. They have done a nice job of making them sound rounder and fuller but they just don't react with the strings and speakers like a tube job does.