I had plenty of issues unfortunately.
This upgrade of theirs was more of an insult to intelligence than anything else, and I should so badly have seen it coming, but I fell right into it like a flipping moron.
Here are the things I discovered on my less than six month old system having upgraded from 8 to 8.1 via the marketplace - where dragons be, and 8.1 was one of 'em.
For a start off, it demands an MS account. I immediately don't like anything that asks me straight away for any account and demands that I be online simply to log into my system.
I noticed that unless I automatically connect to the internet on starting up, I'm actually increasing the amount of time it takes for me to get into MY desktop, with MY files and MY settings. Not Microsoft's, but mine. I wish they would realize these are ultimately our computers they are borking with these stupid ideas of theirs.
The start button was not impressive, it was just a simple matter of removing the big clunky start screen hot corner picture, and replacing it with something that "looks" like a start button on the taskbar. This has to be one of the most pointless tweaks to the upgrade that really hits home after the online account login malarky.
The new Start screen was nothing amazing, nothing short of what I'm already looking at when I'm looking at a phone. This is not a phone, it's a computer. Why do this? Its looking better, sure but I'm not going to spend most of my day looking at the start screen so why should it bother me whether my icons are wide, big, medium or small?
But these things were not the brunt of my problems, in fact that was more of a critique on the upgrade thus far than the REAL problem I got with the upgrade.
I found it didn't like my wireless mouse. It also didn't like my USB device when I so desperately wanted to go back to Windows 8 - which I've just managed to do, but it's still rife with problems now that I have reverted back to windows 8. Sure the mouse works on the desktop, in daily use applications - like Office or just in browsing through the Explorer. But that's pretty much IT.
I did notice, almost immediately on loading a favourite game of mine, that the left mouse button was only firing when it chose to - like some gremlin was hiding in there and saying "my turn", "Ok your turn now"...and then getting really angry and going "my turn now!" and firing off all the ammo in a rifle (actually I was firing a plane's cannons - at which point shortly thereafter I was shot to hell -because I had no ammo left!).
Then there's skype. Well it worked in so much that it would let me see them and them see me. But the microphone wasn't working properly. I tried all manner of things to get the in-built microphone to work, and it simply was not having it. And I've never had much in the way of problems in getting Skype to work before....until yesterday whilst getting stressed at the mess this upgrade really was.
Then when closing the call where I could see them and they could see me (actually it was my Mom ha). . .I tried getting in touch with my girlfriend, currently back at her mother's and not returning for another two weeks. The camera thought it had had enough for the day, sod you, I'm not working ever again...and that was it. It then decided to tell me upon a retry, that the microphone wasn't functioning properly. So I spent hours trying to find the problem, updating where I could. And I could not get the damn thing to work at all.
I have to say....Microsoft need to stop consuming whatever it is that they're consuming to come up with these hair-brained half-arsed upgrades, and stick to working with 7 when it comes to computer OS's.
That was more of a rant after a while, sorry about that.
I should point out it's not very good ultimately. I had to revert because of the problems I had amassed - including an almost 140% increase in boot time - and frankly....I am now actually at the point after over 20 years as an MS OS user, of getting fed up of the devil that I knew once, but now don't know and don't wish to know. That's how well it went for me