What's to prefer; tube preamp or tube amp?

My thoughts are that tube preamps are more popular because they are not driving the speaker load. Many audiophiles use low impedance speakers or other difficult loads that may not be ideal for some tube amps. However, there are quite a few tube amps that can deal with difficult loads rather well. In certain cases, though, there are some speakers that are so difficult that a SS amp is virtually required to drive them. I try to avoid those speakers, so I can use tubes in both my amp and preamp.

if you get tube research driving any speaker is not an issue.i prefer tubes over ss in most applications. however if forced to live without tubes give me gryphon . i would say start with a tube pre then try an amp.

I'm talking stators here and I think I need BOTH tubed, preamps and amps, I've lived with Gryphons a long time, Kirk, The Ref. Mono 1 and the Electra, however with electrostats they are easily bettered both in speed, soundstage and transparency by every Spectral preamp and amp that I've tried. So for me, if not tubes and preferably Jadis, Spectral is my SS choice. I would also start with a tube pre and later try a tube amp. You should however, if driving a SS amp with a tube pre see to it, that the impedances match, which with modern tube preamps should not be too big a problem.