From Moto G to Lumia 630.

I've not used the 620, but do own the 520 (and as of this afternoon the 920, along with the G and the original HTC One.

I'll take the Moto G over the low end windows phones for the screen res and cameras (with rear flash). That's me, personally. I have the 16gb Moto G and I think 16 is neccessary for Android. 8gb or less is a doomed phone, imo, and that's something Windows Phones can handle much better.

I personally find 1gb of ram necessary on Android, and 512 the floor for Windows Phones. They're comparable performers.

Moto G battery life, for me, personally, has been absolutely fantastic. That's a plus in my mind.

I look forward to owning and using all these devices. I enjoy all the platforms.