This is my first, so I am brand new to Windows Phone. Just got my Lumia 521 yesterday, coming from HTC Sensation 4G.
First impressions, I like the phone. Very snappy, light, and easy to set up. Screen looks crisp to me and I like size of screen.
I have tested the camera and it is far better than the camera on my android device. Although, no flash. But I knew that.
Battery life so far seems much better than my android phone. But it will be a few work days until I can really put it through the test.
Things I do not like:
the plastic beveled back. It makes the phone very hard to handle when I try and use the power button. It actually sprang out of my hand twice last night messing around with it. Luckily it landed on the couch next to me both times. Putting the hardware buttons on a beveled surface seems to be a poor choice in design. I ordered a cheap gel case for it, hoping that will help with the slick feel and give me a better grip..
The biggest issue, and this apparently is with all windows phones, is the lack of different volume controls. I like to keep my ringer loud and my media and games at a different level. Seems to be a very elementary thing to leave out of the OS. I almost returned it for that one reason. But I am going to stick it out and hope that an update will bring this functionality.
Beyond these issues, I like everything else about the windows 8 OS and this phone. It compliments my windows 8 laptop very well.