Best mail app on WP8.1

I an looking for the best mail app on WP, which has already updated to all the 8.1 niceties. I was hoping for features similar to the metro version of outlook (which has the categorical sorting of mail, like newsletters, ads, etc...).

I was hoping some people had some good suggestions for this as I have 4 mail accounts I wish to manage, where 1 in Hotmail, 1 is Gmail, and 2 are .edu (managed by gmail).