Thinking about giving the try but trying to find some feedback from former iPhone users.
So, I didn't switch to an Icon, but I've switched many times and can probably give you some unbiased feedback. Some qualifiers for you: I grew up hating Windows because I was a DOS and Linux guy. Windows 7 was the first Windows I liked using, and Windows 8 nailed it. I don't like iPads at all - I don't think iOS scales up very well - and I use a Surface RT. I think Apple nailed the iPhone, that's a great piece of work even given the boring staleness sometimes associated with iOS. So I'm neither a Microsoft nor an Apple "******".
I have two lines - two phones - which I carry with me all the time: work and personal. My work phone is company-provided; it is, and will always be, an iPhone. Currently it's a white iPhone 5S. My personal phone changes almost as often as I change my clothes; since the release of Windows Phone 8 I've had a Lumia 920, a Lumia 820, a Lumia 520, an HTC 8X, an iPhone 4, and an iPhone 4S as my personal phone.
Switching from an iPhone can be really easy, or it can be a pain in the rear. If you're well entrenched in the Apple world, it'll be the latter. If you're the type of person who is a cutting edge app hound and download the latest apps from the App Store as soon as they come out, it's going to be painful. Here are some things to be aware of before you make the switch:
* As mentioned above, if you use iMessage it can be an ordeal to get out of the iMessage system. Until you do, this means people who used to iMessage you will have a horrible time getting messages to you. According to Apple, turning iMessage/FaceTime off and then signing out of them on the iPhone before you switch should remove your number. If that doesn't - which happens for many people - changing your Apple ID password should help (doing this logs all your devices out of iMessage/FaceTime). If that doesn't - which happens for many people - you have to call Apple support. I just had this problem myself, luckily changing my Apple ID password did the trick for me.
* If you've bought a lot of iOS apps, you're SOL. You're going to have to buy them again, and there's a chance you won't find the app or you'll have to settle for something third party. If your iOS apps are important to you, research their availability (or the availability of functionally similar apps) before you switch. You don't want to blindly switch only to find that your bank doesn't have an app and you can't live without your bank's app.
* If you've been buying music from the iTunes Music Store for a long time, a good portion of your music might be DRM protected. In that case, those songs are SOL - they won't play on Windows Phone. Some of the non-DRMed music might not play as well, depending on the format you downloaded from the Music Store. Luckily, iTunes can convert non-DRMed songs to MP3 fairly easily, and DRMed music can be burned to CD and re-imported as MP3s... but if your music collection is large, that might be exceedingly time consuming. If you're willing to pony up $10/month you could get an Xbox Music Pass and rely on the Xbox Music Cloud matching ability, but the iTunes catalog is MUCH bigger than the Xbox catalog and many songs might not be found.
All of that said, Windows Phone is a worthy candidate and oftentimes a breath of fresh air. I'm not saying you shouldn't switch; truth be told, I prefer Windows Phone. I'm just saying that if you're well entrenched in the Apple world you need to do your due diligence before you switch...
...otherwise we'll all have to read another thread here on WPC about why Windows Phone doesn't have this app like iOS or why it doesn't have this feature like iOS. And I don't want to read any more of those, heh.