Of course the biggest issue if you have a Windows phone is that you can't receive calls....
That's right, if you are on a 4G network, Windows Phone doesn't hand over from 4G to 3G properly, so the other party can't actually call you. It's a bit of an issue for something that is supposed to be a phone and happens rather more than anyone would like you to believe.
Apparently EE have raised it with Microsoft, Nokia and HTC, but still, I have a 4G phone on a 4G price plan that I can't do more than 3G+ on because the phone software is crap.
To be fair, one of the fixes in iOs 6.1 was because iPhone5 also had this problem, but still, six months later and the Lumias haven't been fixed. I could rant for ages, but frankly right now, I'm a little fed up and subdued and there is little point. I await the reduction in Tariff I get from EE for the remainder of my contract thanks to this...
And I know there are people out there who will say "Serves you right for buying a WinPhone"...