What was the first reason to buy Lumia 640XL?

I was in a terrible fix over what phone to buy after my iphone 5 retired. Was dwindling between 730 and 640 xl. But finally I decided to bet on Lumia 640 XL and got the phone yesterday, thinking primarily about the points :
1. Cameras
2. Battery Life.
3. Smoothness of OS in quad core chips.
Well its only a day old but i've not settled. Camea is good outside (read it good, not great); but similar to L730 inside.
My question to fellow 640 xl users: It seems the selfies taken with 730 are better than this phone.
While I was thinking both have same module. Is it so ? Whay you guys think ?