Note that it may not be quite right to compare the price with the barebones NUC though - we do include 4 GB RAM, an SSD hard drive (we're hoping for at least 64 GB, if not more) and do some manual work in pre-installing Ubuntu on this (no Windows tax!) so you have a fully-working system out of the box.
With the NUC, you would have to buy the components yourself and install Linux, which would likely come to the same price point (again, we realize most HN readers can do this with their eyes closed.)
EDIT: as for the $20 "supporter mention during the installer" suggestion - we want to install stock Ubuntu, so this might be hard. We can probably put up a perk that involves having the contributor's names on our website, etc.