Oh, is that one of those Windows phones? I've heard of them but I've never actually seen someone with one. Do you like it?
I know you didn't ask me, but I like the Windows OS quite a bit... as planemo said, the biggest downside is that it lacks apps... or worse, they're more expensive than they are on other devices. But really, it depends what you're using it for and for me, windows devices are probably the best.
I don't have a phone, just a tablet... but I have tried all 3 systems and windows beats them all. I like the live tiles that are constantly updating themselves, the browser is better/shows flash, you don't need to worry about viruses so much, there's more memory, there's a USB port, micro HDMI, and the built in apps are great.
I guess I'm gushing here but yeah... I'm not going to switch back unless they take it off the market.