There have been endless articles on how Windows 8 sacrificed desktop usability for being a better tablet OS. The problem is, it’s not a very good tablet OS either.
The problem has nothing to do with Metro per se. The problem is that Windows still, at its heart, behaves like a 1990s OS. Let me walk you through some things that I think, regardless of whether you’re a Windows, Android, iOS fan you can agree that these are inexplicably bad things.
For full disclosure, I have both a MS Surface and a MS Surface 2 Pro, my SP2 is my main “carry with me” machine.
#1 It often isn’t available when you want it to be
Want to check a quick email or look something up? Too bad, there’s an update that has be installed first. There’s always some update forcing itself on it seems like (or enough times that I can’t rely on it as my “quick check”

Oh, you wanted to actually use your tablet right now? No, it’s Patch Everyday!
#2 It has terrible sleep power features
I can leave my Kindle Fire, iPad or heck Macbook Pro laying around for weeks and pick it up and the’re ready to go. Not so for any Windows 8 tablet I’ve tried (MS Surface Pro, various Lenovos). After a few days, they’re drained if not left plugged in.
#3 It’s slow or not reliable at acquiring WiFi after sleep
This is a pretty well known issue that you’d think they’d have fixed with Windows 8. I even picked up a new MS Surface Pro 2 to be ready for next month’s Build conference and low and behold, about a third of the time it won’t reacquire (or is very slow) to pick up the WiFi network at my home or at my office. I’ve had to reboot it before just to get it to see my WiFi. Android, Mac, iOS have never had any issue with this.
#4 Its version of “Sleep” is really more like a light hibernate
You go out to a business lunch with your trusty iPad. You want to pull something up real fast. You press the home button and it’s back on, instantly. Not so on a Windows 8 tablet. You’re going to get the Surface logo (or whatever logo), wait a second. Get to the logon screen, you lift that up, hit your security check and THEN you’re in. That’s insane for a tablet.

Oh thanks!

But you’re one of the biggest offenders!
#5 There’s no “launch” bar on the Metro screen
Android and iOS recognize that there’s typically just a few things you go-to on your tablet all the time. Not so on Metro. I want to get to my camera, I have to remember where I put it (before we made Launch8, I just put those things at the start of the list but it still required me to go back to the beginning of my start list to get to them). This shouldn’t require a third-party program (same is true of ModernMix and Start8, hey thanks MS but I’d rather have the OS be solid out of the box).

Why isn’t there a launch bar by default?
#6 What time is it?
Seriously, how often do you quickly look to see what time it is (or how much power you have left)? On Windows 8’s Metro, you have to bring up the Charms bar to get that. What? Why? Not even something on the Start home screen? You have room for my name on the home screen (top right – thanks! I forgot who I am!) but not for the time of day or battery.

Thank god, I forgot who I was. Now, what times is it? How much battery is left?
Bonus: This isn’t an OS issue, this is strange hardware design issue so I’m not including it into the list: Its “home button” isn’t tactile. People who use tablets often use them in low lighting. It’s incredibly frustrating not being able to find the Windows button. Why do Windows 8 tablet manufacturers seem to insist on not having a tactile Windows button?