13.04 installed just fine on my new (UEFI) PC!
Didn't even have to Disable Secure Boot. Looks like Canonical has a Microsoft Secure Boot Driver in 13.04.
2013 Dell Inspiron 15 3521 Laptop, 2010 Dell Inspiron 1012 Mini Net Book, 2010 Dell Inspiron Zino HD 400, Sprint Samsung Galaxy S4, and Apple IPad Mini WIFI Only.