The new Asus Chromebox arrived a week ago, so I've had a chance to break it in and see what it can do.
So far, I haven't really noticed that it has half as much RAM as the older Samsung it replaced. In one week I've had exactly one page crash with an error message along the lines of "Chrome may have run out of memory or there may be a problem with the page." Given that I only had a few tabs open at the time, that I frequently work with 20 or more tabs open and that on refresh the page came right up, I doubt it was lack of memory.
Over the course of my computing life, I've noticed that all non-Mac machines seem to have their own small quirks. The Samsung would sometimes have trouble coming back from sleep/suspension to two monitors. The Asus sometimes comes out of sleep/suspension with the keyboard not wanting to work right (some letters work, some don't). In both cases a restart (a matter of a few seconds with a Chromebox) fixes it. Right now I'm using a (pretty worn out -- about half the keys no longer have visible markings; fortunately I'm a touch typist) USB keyboard and a wireless USB mouse. I'm planning Real Soon Now to buy one of those wireless mouse/keyboard sets that work through a single USB dongle for both devices and see if that gets rid of the keyboard weirdness.
My recommendation, as usual: If your computing life takes place pretty much entirely on the web / in the cloud (or if it could), your next machine should be one of these.