I'm a big fan of services like Parse & Firebase so it's cool to see something open source and independent get released. I've never made the jump to use Parse or Firebase in production though because inevitably I have to write some custom server code to do some integration. For example - payments with Stripe. Charges should only occur on your server (not on the client) but I've yet to see anyone allow you to configure…
I also do have custom server code, which was a little bit tough to get going, but it's great having a dedicated Linux box as well.