Solid state preamps can sound great objectively, but tend to have a mechanical presentation, whereas the best tube pre-amps reproduce the organic quality of real instruments and voices. But I differ with many above and prefer a tube power amp over a solid state amp any day. I don't see them in the same ball-park unless you have a pig of a speaker to drive and a small budget. I have tried a large number of solid state power amps and the only sweetness they ever achieve sounds utterly artificial to my ears. Give me the real honey, not saccherine.
SS vs Tube: What do you hear?
Peter Aczel, editor of The Audio Critic, says "Whatever vacuum tubes can do in a piece of audio equipment, solid-state devices can do better, at lower cost, with greater reliability" (issue 26, p5). What do you hear which causes you to select tubes over ss, or vice versa?