With Linux because I didn't like Unity desktop I was able to wipe Ubuntu install Mint and have virtually the same OS with a UI I liked, Windows 8 users won't have that luxury.
THIS is the kicker - this is Linux's strength, and unfortunate weakness too. Before Windows 8, average Joe didn't want UI options, and was even confused & afraid of them. Now, in post-Win8 world, people hate the change and refuse to budge from older versions, and this is where Linux could step in with an "Hate new-look Windows? Take a look at this!"
Getting back to the Ubuntu/Unity thing in spite of how i felt about Unity I think Cannonical has done a far better job of integrating the touch UI with the desktop than Microsoft have done with Metro, if only they could get it on hardware and in retail shops they could've be on a winner but it looks like (once again) they're late for the party.
In some ways, it's annoying that at this time, Canonical are looking to the future, and to tablets & phones to get Ubuntu out there, rather than going for the jugular as making a big stab for the desktop/laptop market with OEMs and retailers.