I have an Acer C720 myself but put ElementaryOS on instead of Ubuntu - runs like a dream and looks great to boot.

A good thing about the C720 is that the SSD is upgradeable fairly simply[0], though it's easy enough to stick an SD card in as a stopgap.

I picked up a refurb (not that you'd know to look at it, feels brand new) for £130. Wouldn't get an 8.5hr lightweight laptop for anything close to that elsewhere.

[0] http://www.thessdreview.com/daily-news/latest-buzz/acer-chro...