What I'm most interested in is the latency (I guess that's more or less the same as "snappy"). Back when I had a netbook LXDE was one of the few that felt good.
There's certainly some added latency in GPU composited desktops so a lot of the time that has an effect with modern desktop environments and/or wayland vs LXDE which as far as I know doesn't run a compositor.
I'd love to find some good testing on it somewhere, but I do recall off the top of my head that Windows XP or Windows Vista/7 (with Areo disabled) had significantly lower latency than the GPU accelerated counterparts in Vista+. I believe it has to do a lot with Vsync, but imagine there's some additional overhead involved as well.
Of course many would say removing screen tearing is a valid tradeoff there, I mostly agree but not everything is significantly effected by tearing either.
