I am using Windows phone since 2 years. I am having two sets- Lumia 525 and Lumia 820. Both the sets are now old but they are best as they were manufactured under Nokia.
The hanging of phone in windows phone is very rare to see. The touch provided by them is ultra smooth and sometimes it responds to touch before just touching the screen. The camera provided by Nokia and Microsoft gives a clear resolution in the range if compared to other phones. The light absorbing tendency of lens is superb. The store in windows phone offers some great valuable apps but they are limited if compared to android. A number of apps are paid. The sound quality of speaker and calling one is very clear and amplification is also good. Since I am using Windows phone when its under Nokia therefore the best part is that the phone made by Nokia are very strong and battery back up is so efficient
In windows phone they cannot bear many OS updates as now after a number of updates my phone starts to lag.