I won't defend the bad UI but you can get to the charm menu just by using Windows+C. Also, installing ClassicShell takes literally thirty seconds and then you have a standard Win7-style UI. The kernel and other OS internals in 8.1 are faster and more stable than 7.
You tricked by update cycle. Each new version is faster because has no updates that fix holes. Test it, install new virtualboxed w7sp1 into w7sp1 with updates and feel the difference.
That's the reason why I never install updates (this forces me to be ultracareful on the web, but I'm ok).
While you were 'in doubt' I recently reinstalled my old laptop (with the same restricted set of software except updates) so it can boot quickly and open explorer instantly, not in a couple of seconds. This behavior disappears at the time you install all updates. I experienced that many times on many pcs. Not that you should trust me, test it.
