Am a MSDN subscriber so also had legit download which I did late Monday. 8.1 Pro DL went ok, but I could not get the bootable Flash drive to boot on my SP 128 (either a 32gb USB 3.0 nor a 16gb USB two). So just did a "save none of my stuff" non-upgrade install on top of a straight 8.0 Pro install. Worked fine and used Disk Cleanup to get rid of "Windows.old". After loading the usual Windows suspects, including Office 365 and Visual Studio, then adding Vipre and Diskeeper, I still have 90+ GB left for use. Add to that my 64GB SDXC where I save all my stuff, and the SP is doing just fine with 8.1. I had used the two 8.1 preview programs this summer for about a month each, but had issues with the drivers, especially the Marvel 350n network adapter driver - which is why I had gone back to 8.0 Pro whose drivers did not act up so much. Things went well until this AM. I like 8.1 and the smaller tile capacity, start button and the solid, professional feel to the OS. But I play only one game, SpellIt, and it messed up the network drivers in the preview versions and now it seems to be doing the same this to the RTM. So once again I have to uninstall Spellit until we can figure out what's what. Ah well, Spellit works on my WP8 Nokia 920 so I won't miss my turns at getting clobbered. Maybe I will have to wait until the SP 2 comes on the scene, but gotta convince the house treasurer that it will be money well spent and that's without telling her that she is getting my 920 and the SP128 so I can also get a Nokia 1520 phablet AND the SP2. Hand me downs are not so exciting to her.