Hi Greg. Been there and done that.
First up: interplay between price and quality. Not a difficult concept in itself but it gets a bit more complicated with the variable of tube vs SS. That is to say it is more difficult - and thereby more expensive - to produce an equivalent quality tube pre amp. The main issue is in getting a truly low nice tube design.
Second: There is a bit of a continuum. For SS then mosfets sound closer to tubes than bi-polar transistors. Likewise 6H30 tubes have more tube sound than others.
My take for a pre (given that I like valves): Do not bother unless you get a very high quality (and expensive) valve Pre that runs 6H30 tubes.
This is not so easy. I have an Ayon Eris but I prefer to run my Emm Labs or Daniel Hertz Pre. The Ayon is good but the Emm and the Daniel Hertz are just lower noise.