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

I wonder what is to prefer when it comes to amps. A tube preamp or a tube power amp? Many people seem to like the preamp to be tube. I also wonder what the difference is? And what about both amps tubes? And why not an integrated tube amp? Thoughts and question marks that I would like to have straightened out.
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.
I found tube gear adds more life to the music.
As far as integrated goes, it works but can be better.
Seperate power source usually works better. You get better dynamic and less heat issue with preamp+amp combo.

From Tube FAQ,
" Tube is a totally mechanical device, inside a tube is just some metal plate arrangements, the effective operation area is much much larger than a semiconductor (sometimes even 1,000,000 times larger). When music signal pass through a very small area, it will implies certain squeeze feeling to the signal itself and it is very noticeable , so when a signal just pass through one transistor, you will immediate sense the compressed , flattened and hardened feeling from the music. The more the transistors in the circuit, the lesser the easiness more and more flatness and hardness to the music. "
don't forget that tubes in a preamp last longer than an amp, so the cost of replacing tubes is more efficient in the long run.