Sometimes different, sometimes similar, sometimes hard to tell apart at all.
Like most things, it all depends.
In general, the sound of "good quality" tube gear is more variable than good quality SS. If you like a certain flavor of sound, tube or SS but not both may be the only option. Both are capable of very high levels of technical performance (not to be confused with what a particular individual might deem to "sound good") that tend to sound more similar than different when done right.
Tube rolling with a lot of tube gear provides a unique way to tweak the sound not available with SS gear.
