In (slight) defence of your friend, a Marshall Valvestate does what it does perfectly well. My first guitar amp was a dodgy 35w Peavey of some kind or another, and I sounded a hell of a lot better when I changed it for a Valvestate 8080. And then, things sounded an order of magnitude better again when I retired the Charvel Charvette in favour of a Gibson LP :). I knew I didn't sound as good as I would through an all-tube amp, but I sounded pretty damn good, actually (like the punters cared!), and it would have been some time before I might have decided to change up to a 50w head or something (100w would probably be more than I needed!).
The Valvestate (still sitting in my parents garage in the US, waiting) was very cost effective -- as was the Laney TubeFusion hybrid I used over here. As for the Gibson LP ... OK, pimping an Epi might have been more cost effective, but I didn't think so much that way back then, didn't have access to forums full of clever guitarists :), and had serious Gibson-lust that needed slaking! (That said, I was in the US and got a decent deal on a second-hander, so I can't say I'd do it different now :).) On the other hand, I weren't gonna buy no "Studio"! Only the "Standard" would do, all or nothing! :)
All right, I suppose some people might actually prefer the tone of a hybrid or solid-state combo to an all-tube -- but that's weird! ;) For most of us, all-valve will sound better. And I don't even like multi-FX units, never did. But even modelling has its place: I like being able to record decent sounding demos quick, easy, and silent at home -- and trying different amp types. And I could always get a real tube amp or two someday and run them through a hotplate into my digital cab sims (probably easier than building a bunker in which I can cut loose with mic'd stacks :)).
But everyone has different priorities at different times, and the key thing is to use what you like and are happy with wherever you are. You can always sell it on later when you change your mind (and you probably will :)).
