I like how easy it was to get started with this product, as well as being able solve my issues of getting our products ready in time before launch! It's not perfect by any means but we've been using their services since they launched last year so there isn't much more information about what works or doesn’t work yet - just keep plugging away at solving your problems one-by-one until you do :) The biggest issue right now (and likely something outta scope) would be having better integration w/ Google Play Services & Firebase Authentication across all platforms including Android Studio builds etc..
We are currently looking into integrating them ourselves instead which has reduced some headaches down from managing multiple different accounts / passwords throughout team members' devices however nothing beats good ol fashioned google auth ;).