I have a iPhone 5s and Android phones (GS4, Moto X, had a Note 2). I'm currently using a 928. I tend to switch between phones, but am trying to stick it out with WP. With iPhone I felt I had a device that could handle every need, but longed for a bigger screen. Android filled the need for the bigger screen with apps that fit most needs, but not as nicely as the iPhone. The 928 is a great phone with a great low light camera and WP has a very nice design aesthetic. The apps fit most of my needs, but the I miss the occasional app like TiVo, Chrome browser, Amazon video, a solid YouTube app that doesn't get screwed every now and then with some Google update, etc. There are 3rd party apps for WP that fill the remaining void, but just aren't as nice as their official IOS counterparts (IM+ in place of Cisco Jabber for work, Dropcam replacement, Metro Voice, Metro Tube, etc). I do enjoy the MS office and Exchange integration as it comes in handy for work. I also really like the live tiles and don't really miss a "notification center" as much as others. It's a real paradigm and mental shift in some cases (ex. Using people hub for social media updates vs. using each individual app), but one that is very nice once you get used to it.
All in all it depends on what is important to you. I'm trying to give WP a chance to see if I really miss the small things or if the better low light camera performance, having something different, integrated social media, etc. will win in the long run. I also just got a Surface Pro 2 and am really enjoying that too as so far it seems like it could really replace a work laptop.