the windsor is a cool sounding amp, ive never owned one but ive played it in person a couple times. Daunt from this forum did a recording of one some years back that was pretty amazing, so its definitely possible to achieve a great recorded tone from. If you google on them long enough you will find horror stories about the occasional person who got a lemon. I think for $200 its pretty hard to beat and low risk.
The valveking sounds ok but not marshall-like to me, and the amp feels a bit stiff.
If you wanted to consider other options that are actually marshall there is the marshall 3203 which goes for around $400 all day and has a tube power amp and can get in 800 territory with the right dirt box, it is well regarded by most who have tried it. Or you could get a first run valvelstate, people love em or hate em but if you want high gain with that marshall voicing on the cheap it might be right up your alley. I think most marshall products Ive tried have a common voicing. In general it seemed like most folks with Windsors modded them up or at the very least replaced the factory tubes so you should consider that into what you spending as well.