Hey!
I did the opposite of you, after many years with android i did give a try to WP by buying a low cost device.
After finding myself constantly fighting for the same things over and over on android, something keeps missing and the OS version doesn't matter at all neither the device. I went to buy a WP low cost device so i got myself a lumia 630.
So far all i can say is that Android compared to WP it's a constant draw of something that keeps changing to a new OS version every time google gets tired of fixing a previous OS. Then they start another cycle until they get tired again and re-build a new OS.
Pros
-Thousands of store apps.
-Lots of personalization.
-Funny during the first three weeks.
Cons
-API is bad for nearly every single app.
-The lag, i can't understand how a device with 1gb of ram and a quad core processor keeps lagging for no reason.
-Repetitive, install launcher, uninstall launcher, apply icons, change icons and still something keeps missing.
-OS support, you will only get it regularly if you buy a high end device.
-More apps you install, more battery it drains.
-It goes slow and crashy with time.
-The whole structure is heavy.
-The market its so big that makes it hard for a low/medium device to get updates from OS to OS.
WP surprised me for real, even that i like to push the boundaries and bought a device with 512ram and it is lagless with all the possible social apps installed. The structure is pretty light, apps api are very well programmed. I can rely on WP for real. With a WP device i can do things i never could with a android with the double of the spec of this lumia 630. It's a whole different and very well done approach. I just love it.
Pros
-The whole structure.
-The minimalistic design.
-Simple, fast, intuitive and definitely reliable.
Cons
- 3 years of development seems not enough to implement a mobile data toggle on the notification center.
- No fast reply from the screen.
- Still too awesome to not buy one.
Still these two OS are different it's like Android is for fun and WP feels like a serious OS willing to do what you want without any questions.