So I've had my neutrino up and running for a few days now. It's been quite fine. Other than one or two random hiccups in the netbook remix of Ubuntu 9.10, it's been smooth sailing. Startup is easily three times as fast as my HP Mini was (due in no small part to the components the Neutrino can take). I'm still gobsmacked by how much actual difference the matte screen makes, by the way. My HP mini travelled with me quite a bit, and it tended to get a lot of gunk on its screen (judging by the pattern, it was being picked up off the keyboard when I closed it, despite the fact that I kept a cleaning cloth between the board and screen), it also reflected in all sorts of lighting conditions, to the point that I couldn't actually use it on the bus or streetcar a large part of the time. The Neutrino doesn't have either problem. The matte screen takes care of most reflections, and it's slightly inset, which means the surface never makes contact with the keyboard.
Sound and webcam are both much better on the new thing, though I don't have much occasion to use either in my daily activities. I also haven't gotten to testing out how it works with a second screen. Again, really no call for it. When I'm out and about, carrying a second monitor is impractical, and as comfortable as the neutrino is, when I'm at home I still prefer my desktop colossus.
What I have found is that Xmonad helps. I'm still not a haskeller, though it's quite tempting to drop everything and learn it given what I keep reading about its performance, and Xmonad may finally push me to pick it up. I doubt I'll ever use it on a desktop machine (or for that matter, on my netbook if I have it hooked up to multiple monitors). It's set up to be minimalistic. Which means that a whole bunch of things you take for granted in GNOME need to be done manually (like connecting to your local wireless network, or setting up keyboard shortcuts/switching out caps-lock, or setting up a way to launch programs other than the command line). It's really all stuff I should know anyway, but I don't need to with my usual routine.
Just to remind everyone, I live in exactly three applications (with two more coming out very rarely for specific purposes). The three are Emacs, GIMP and a browser (which one varies depending on what exactly I'm doing at the time). On some rare occasions, I bust out Inkscape (to edit vector images) and DrScheme (for the fantastic macro-stepper). Ok, yes, fair, I also use Klavaro for keyboard training and Rhythmbox for tunes. The first one gets run once per day, and the second is a fire-and-forget program.
You'll notice that Terminal is no longer in that list. That's because these days when I need to do something terminal related, I either whip up a quick Emacs function and bind it to an appropriate key-combination (if it's a command I find myself using a lot), or I use M-x term rather than hopping out of Emacs, possibly hitting C-x 3 first to get another vertical window fir my terminal session. In other words, the way I use my computer, Emacs is my window manager. GNOME is just there to take care of the background bullshit like connecting to wireless on my behalf, keeping the system clock ticking, and letting me know when there are updates to be had. Other than my Emacs monitor, all screens are taken up by exactly one window, and I tend to organize several workspaces (each oriented for a specific task) so that I can switch as seamlessly as possible.
So I don't see Xmonad usurping my window-manager of choice.
That said, it has one very real advantage to GNOME, and that's a lack of status and toolbars. That's two additional vertical lines of text. It doesn't sound like much, but it's worth quite a bit on a 10" screen. Since I never really connect to wireless nets while I'm on a bus/streetcar/subway, the advantages of GNOME make no difference there. So, while I'm on the go, Xmonad is a superior window manager for my netbook. Granted, all I do is run the one instance of Emacs, but that's all that's on my screen. No toolbars, no status bars, just one giant Emacs window with minibuffer. You'd be surprised how cool that feels if you're a big enough nerd.