Great comparison. I am going with Firebase for quick and dirty PoC and sticking to Amplify for futuristic production grade solutions - ! BTW Why do Google keep killing their projects - lack of focus in strengthening the ecosystem and marketing - this sucks - the future is scary if I were to choose Firebase - already the Git number says it all - the direction of Firebase!
Amplify does have DataStore with subscriptions and observables for realtime database type implementation. I find it a bit of a pain but it absolutely works.
