Inexpensive, beautifully designed, quiet.
I can see Acer's point of view in not pre-installing Ubuntu and it's very simple - they don't have to.
As it is, they have made installing it as simple as possible by shipping the right kit:
Out of box, wire up, netboot Ubuntu USB stick in, press F12, select USB boot drive, type in network parameters, select desktop, sit back.
15-20 minutes later it's running Ubuntu.
You can go to nVidia and install the 3D accelerating drivers too, which consists of one download and one command.
Everything (wireless, audio, network, graphics) works straight out of the box.
This is, without any doubt the future of home computing.
Oh and mine came with a (apparently silent) 160Gb drive too.