Some will complain no matter what. I still question jamming the two different user paradigms together the way they are. "Metro" apps running in a window ... ok, fine. It's still an ugly ass "Metro" app.
Speed wise: quite acceptable. Seems to be a little more resource hungry than Windows 8.1.
My config:
AMD FX-8350 8-Core @ 4.8Ghz (overclocked)
32GB 1866 DDR-3 RAM
Samsung EVO 840 250GB SSD
GEForce GTX 660 SuperClocked Video w/2GB 1866 DDR-3 Ram
If Microsoft insists on jamming Metro Apps to the "start button" that they're showing, I'll stick with Windows 8.1. I've no compelling reason to change. I have my machine configured the way I want it, I use a third-party Start Button and Themed my machine to look like Windows 7.
I don't want to re-do all that work.
They are customizable and removable. I like having them there personally. Quick access to apps, live tiles with mail updates, news updates etc without launching is nice.