I used to be an iPhone user having had the iPhone 3GS, iPhone 4 and iPhone 5. However, I was sick of paying stupid amounts of money for a phone. They are great, but just not worth the money, in my opinion.
I have never gotten along with the Android OS so I thought I'd look at Windows Phones and I don't regret it. I loved the look of this phone online and it has not disappointed in reality. It's very slim, lightweight and good to look at.
The OS is so simple to use and once you have your Microsoft account set up you can download plenty of apps and games to it. Most of the popular ones are available now. I love the tiles on the home screen. Quite a simple idea but very effective and you can personalise your phone to display whatever is important to you. Simply swipe left and you can access all apps installed on the phone, in a simple alphabetical list. It can't get any simpler. The phone has a great camera. Despite only being 6 Megapixel, it takes excellent and clear pictures. The screen, despite being a mid range resolution, is very clear, vibrant and easy to see / read.
What stands out the most is the battery life. It lasts me three days of light use (30 mins to 1 hour of calls, several texts, accessing emails several times, checking Facebook and Twitter, listening to music plus playing games for 20 mins or so). I'd guess medium use would give you a couple of days and heavy users should get a full day without worry. It has a battery saver feature that switches off certain features to extend the battery life too.
I really can't recommend the phone enough. It's really nice and very easy to use, I'm delighted with it.