Tubes V. SS is like color V. black and white photos. But the above comment about proper matching of components is important. Black and white photos can be very impressive, and SS can sound quite good with the right associated componenets.
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?