They all sound the same!
- Well, they should do if the load they're driving doesn't stretch them in any way and they're not pushed to clipping....
You know, it's not really the technology used, but HOW it's used that's the thing I feel. I've heard solid state amps which are grainy, harsh and nasty to listen to for long periods, especially if played a touch too loud (I'm talking new amps here and Naims of various periods all have some of these characteristics to a greater or lesser extent - they've gone from one extreme in the mid 70's to the opposite in the mid 80's and are slowly trying to gain the middle ground again, limited by the ancient and *apparently* PA nature of the original circuit), yet other ss amps can sound pure, atmospheric and almost velvety, not hugely different from their valve ancestors (Quad 303 and well sorted examples of their current dumpers - IMO). Some modern Sugden ss amps sound as if a thick blanket has been thrown over the spesakers, a deliberate design quirk IMO. On the other hand, in recent times, I've heard some of the Icon Audio range (not the wacky ones) and these, range from soft and almost thick toned for the £1K model to neutral, clear and utterly clean without any harshness in the copper topped Stereo 40 (I think) and 60 models.
I believe that speakers are the final arbiter, since ALL of them add so much character, colouration and distortions of various types to the listening experience, and this is before they're placed in a listening room! What I feel you need to do is to listen to a few good setups and see how you FEEL about the music being played. Some speakers need the usually extra grip and damping available from a good ss amp, other speakers have a tight enough bass as they are, but may have tweeter or crossover harshness built-in, needing a restraing order at thiose frequencies 
Not really helpful I'm afraid, but many peeps buy valve gear because of the way they look, and since music reproduction is so emotive in the firat place, they have EVERY right to do so in my opinion
I can't go on and I can't go back, I don't feel so matter of fact,
I tried and tried to make good sense, What's the good to try it all again?