Actually from my reading the Marshall is based on the fender amp. So Fender technically is the grandfather of valve amps.
Yep. The 1959 Bassman to be exact. The original Marshall was a 59 Bassman circuit Jim Marshall modified.
I'm a tube guy all the way, no matter what sound I want, I use tubes to get it. After trying to get "the" sound for years out of solid state amps, mostly Kustoms and Peaveys, I sat in one night with a band whose guitar player used a Peavey Butcher full stack, and found out the difference in his sound and mine was tubes. I've never even looked at solid state again. I currently play a 45 watt silverface Fender Super Reverb for raunch n roll and a 120 watt Peavey MX for clean. No matter how loud I crank it the MX stays clean, even at 7, which is the loudest I ever had to crank it, and believe me you don't want to be in the room with that beast cranked to 7. But I was still playing clean leads on top of a rhythm player with a 100 watt Marshall full stack and he couldn't turn it up any more...I was wishing I had some earplugs...but I got a nice clean sound even at 7 or 7 1/2 and I've never seen another tube amp do that...my Super Reverb certainly won't.
So to respond to the original question, I always advise going with tube amps, you can get the sound you're after with any tube amp, brand doesn't matter, the main difference is more gain or less. Some are more reliable than others, some have more gain or less, but blindfold me and I can get the sound I'm after from any tube amp, no matter whose logo is on the front of it...Combo and stack have their own advantages and drawbacks, I'm using one of each. The main requirement for me is it must have tubes or I don't even look at it twice.
So I say look for a good tube amp.