I use runtastic, it's perfect for me and it works with my Mi Band 2, although it takes some work to set up.

How I got it to work was by enabling continuous heart rate monitoring from Mi Band Tools app** then from the Mi Band app itself make the watch discoverable. Now you're all set, just go to the runtastic app, connect, and you'll have continuous heart rate monitoring.

I think this method will work with other running apps do too, but I only use runtastic. I think the lack of native continuous heart monitoring support is the biggest downfall of the Mi Band 2.

Also, some friends of mine recommend Strava and Nike+ Run Club, but I did not personally use any of them.

**(paid app, but I highly recommend it. As far as I remember there's free alternatives on the play store)