It's better on the inside, especially the DLL sharing. (Rather than each running app having a separate in-memory copy of a DLL, now if separate apps have the same DLL dependency, then there's only one copy in memory. Probably my favorite feature of Windows 8)
But the interface still sucks. I've used 8.1 as my primary desktop OS for almost a year now (Stock install, no Start Menu third party add-ons), and while it's a solid OS, there's still so much missing from the Metro interface.
Recently used documents is the thing I miss the most.
And just exploring through the tree-based Start Menu is something I really miss. I end up with so much stuff installed I forget some of it. Would occasionally just surf thru the Start menu to re-discover stuff. But with 8.1, if you don't remember it, you're not going to find it. Sure you can go page by page through all the listed stuff, but that's far more inefficient than being able to walk through a tree-based menu.