After reading all the responses here, and picking up on similar responses on a post that Bigkidz has going, I'm seeing the "vastness" of options in tube amps. Some other models that people seem to hold in high regard are Musical Ref. RM-200, Quick Silver V4 and Berning ZH-270. Although I know these exceed what my scope is, I want to take my time and make a decent choice. It's obvious that I need to research more, and go and listen to as many as I can. For right now, I'm staying put with my x250 until I feel qualified to take the next step. Thanks to all for your input.