Now that I think of it, the only people who have revealed their preferences to me are Windows Phone users. Time to clear that up on my part.

It should be rather obvious that I prefer Windows Phones, largely because they work great in conjunction with my T100.

iOS would be a close second, though. (It's polished, and it has polished games on it.)

I've been using iOS for several years now, and just recently got the HTC M8 (the android edition). I've been using it for just over a week now, and I can say that I like the way android works. I also have had a Kindle Fire HD for a while, so I am somewhat familiar with the way android works. But the stock android experience is very different from what Amazon does with its Kindles. But anyway, I really like HTC; I'm getting used to having widgets and what not, although I probably haven't used them to their full potential, I only really have like two widgets activated, but whatever.
I love exploring the various options in the settings. I really like the app manager, I like that I can hide bloatware, the storage and battery managers. I think it's cool that I can further customize the operating system, with different launchers and whatnot. I haven't done anything like that really, but I have the option.
One thing I don't really like is the google play store, or the amazon app store. Both of them have a bad design compared to Apple's App Store. I was surprised to find that many of the games I expected to be on android were not. Yeah, you have popular games from Gameloft, EA, Square Enix, etc on both platforms, but there were some iOS games from smaller developers that I had been looking forward to playing, that I will now likely not get the chance. But on the other hand, android has the Humble Bundle, which should be very nice.
I have also decided that iTunes is vastly superior to anything that could be offered for android. Syncing music and such is quite frustrating. Maybe it's just the HTC sync manager, but there have been some big annoyances with syncing music and playlists, especially after I moved my music to my microSD card. Android could really use a free media manager that can compare to iTunes.

Overall I really like the Android OS. It gives me the freedom and customizability that iOS never had. But maybe there is too much freedom. Like, I'm not sure I should have the option to kill a background process that will completely crash my phone.

Windows Phone.

As much as I'd prefer the range of apps on other systems, the OS alone makes it impossible to switch for me.

Pretty much this for me as well.

I use Android and like it, but if Windows Phone had better app support I would most likely switch to that instead. I just like the interface more.

I like android cause of the sheer number of customizability you can do! Like, you can make android look and even run (to a degree) like both iOS and Windows phone. Sure, its not perfect and it takes up more ram (at least most flagship android phones have a lot of ram to use, lol apple) but for what it is, it runs very smooth! And of course, if you don't like ur current android "OS" that the manufacturer has put on place, you can, fairly easily, switch to a "different" android one! Like for example, going from touchwiz to cyanogen!

So yea, I love android cause of that! And when ART comes out for android, its gonna run even more godly considering how snappy it already is on the low end phones!

I use Android, but I actually do like iOS (and even OSX) to a good degree. The problem for me is the overpriced iPhones and the lack of some basic customization, but overall I can't say I dislike the actual OS. I've never tried Windows Phone though!

You forgot Firefox OS

Android's customization brings me great joy.

Windows is great but its weaker into apps area.