My first smart phone was the lumia 630. As I get used to, windows mobile is the benchmark. There is an android mobile in the family as well, but I think it is quite gas to use and the lumia is faster.
I'm voting for windows, it really suits me. So much so that there are few apps, but e.g., navigating the map on a mobile level is unbeatable in my opinion. It handles well and even small category phones are pretty fast with it.