You'd be hard-pressed to get any more compact than that, but not too sure about its quietness (yet). You do realise that it doesn't offer much scope in way of upgrades - e.g. internal hard/optical drives or dedicated graphics/sound cards.
My neighbour has gone for the Acer L100 - the Tesco one of course (after another company cancelled her order (click here). She wasn't particularly after a compact/quiet model though. We're expecting it to be delivered tomorrow. G