Yes, I've tried XP and Windows 8 - my machine at work runs 8 x64 on an SSD and it's very quick, actually. For the most part, it's the only machine I've used that rivals AmigaOS for responsiveness. And yes, I'd expect a 2013 PC running a 400MB/s SSD to outperform a 1992 Amiga 1200.
I compare with my own Sam440ep and A1XE (I can't afford an X1000) particularly, although my CSPPC A4000 is still very impressive.
But none of that can change the coding. I've always hated Windows coding ever since the word "WM_PAINT" was first ingrained into my memory. The whole way Windows works is hideous, and whereas AmigaOS now contains Reaction (with which a capable GUI can be built very quickly), Microsoft prefer travesties like MFC and now the Metro interface (which to be fair I've not tried yet).
As usual, it's horses for courses, and we'll probably have to agree to disagree on the old "my OS is better than your OS". But one thing is certain, and I can answer your original question (and I'll make this as clearly as possible):
My choice of OS is nothing to do with nostalgia. It is just a preference.
Now the less succinct version
:
I think there is a tendency sometimes for people to label things that are "old" as "nostalgic", when it's not correct. For instance:
I have a large record collection, and few CDs. Is it nostalgia? No, I just prefer the warm analogue sound to the clinical, digital sound of a CD.
I listen to old music, mostly 60s and 70s. Nostalgia? No, I wasn't even born then. I just think it's more rewarding (give me some nice Rock, Prog, Jazz or something over modern music any day)
My favourite film is "The Producers" from 1967. Nostalgia? No, it's just an awesome film.
My wife spent most of the evening playing Sonic on the Megadrive. Nostalgia? No, it's just a very good game.
My favourite platform of choice is the Amiga. Nostalgia? No, it's just an awesome platform to use and develop on.