For example, while the boot speed looks impressive it's a bit of a cheat as the PC is essentially useless for at least 30 seconds of so after you login while it actually completes the boot process. So whereas booting windows used to involved (i) power on (ii) wait a minute (iii) logon (iv) wait 5-10 seconds, (v) do something, it now takes (i) power on, (ii) wait 15 seconds, (iii) logon, (iv) wait a minute, (v) do something. And the 30-60 second delay after you logon is there no matter how long the system was idling waiting for you ... so you've actually made it waste more of my time as the workflow is actually playing against me.
Metro interface - think of it as a huge full screen start menu that is showing all the time unless you're actually doing something else, with all the "Programs" menu groups expanded and then flattened into a less than useful single huge wrapped list. Oh, and some programs run "inside" this start menu, but they're pretty much all dumbed down full-screen versions of what you can do elsewhere, but they now run maximised and with no easily visible "close" or "un-maximise" buttons etc (try moving the mouse to top left and a button of an image of the desktop will appear to let you close the app).
Hooray - Windows 8 has reinvented the "one fullscreen app at a time and no UI multitasking " user experience of DOS 3.x and all those nasty "Boot menu manager" apps that people used to run so that they didn't have to remember command lines.
And if anything breaks? Well the Metro "Windows Update" now crashes for me (or at least the app vanishes when started). No error message, no error log, just starts and .. poof, gone. Luckily you can still find Windows update via the Control Panel. But now I have an "Important update" that repeatedly won't install and crashes out with no more than an 8 digit error code (80072ee2). Any searches for help little more than Microsoft Support Engineers saying "first, and you really shouldn't do this in general, but turn off your anti-virus, then unplug all extra hardware, and then disable services". This is tech support speak for "We have absolutely no idea what's happening and no way to diagnose it, please call back later or just go away".
Well that's OK, I can "Refresh my PC without affecting my files" via the Recovery options. Except that this needs Windows 8.1 installation media to "authorise" the repair, and of course it won't accept my Windows 8 installation media, so by taking the recommended "free update" to Windows 8.1, any repairs will now require me to basically re-install Windows 8 from scratch and then upgrade to 8.1 again (and no doubt make MORE calls to Microsoft to "authenticate" my use of this product key again).
This is why I hate what Windows and DRM have become, not because I'm not wiling to pay, or I want to pirate stuff, but because it makes it painful to be a legitimate user, and punishes the valid and paid up user by automatically assuming the worst of everyone.
My Linux install, by contrast, has just been tweaked and upgraded and repaired and refreshed and has chugged along thru several entire hardware update cycles over the last 10 or so years - when I broke stuff then yes, it needed work to fix it, but it never once insisted that I can't run some program because my "product key" is for an OEM rather than a retail version, or because I don't have a DVD that I can't freely obtain on another machine.
So, Windows 8 convinces me more than ever that this is not a user experience I want for home. The idea of taking support calls from family and friends and walking them thru "charms" and metro apps and "now read the tiny font on the sticker on the underside of your laptop" fills me with dread. Windows XP and 7 were bad enough, but 8? It's just a huge mess...