Although I don't have the 4.0 beta, I would love to see how good Unity's Linux export is. For this reason, I will try out Unity games that have been released for Linux in this thread. Just zip it up and I'll give it a go on a spare Linux computer I've got.
If any bugs are found, I'll post them here. My distro of choice, by the way, is Linux Mint 13 Cinnamon, though I will try other distros if I can to test compatibility.
Looking forward to seeing some great projects!
EDIT: For this thread that all those OMGUbuntu people are coming from, look here: