They've been a bit slow to implement new features for production, but I understand development timelines are hard to predict.
I think the product is in a pretty good place for a limited release right now. We are really looking forward to synchronous mutation callbacks and multi-region replication (currently only eu in production, us-west-2 and asia-pac are in beta). We're using lambda functions as in-betweens while we wait on synchronous callbacks and it's been totally fine, it just breaks the "GraphQL fits all your server api needs" paradigm.
Edit: it looks like today they just released "request pipeline" which is actually a pretty robust synchronous callback. Impressed at the thought that went into this. -- https://www.graph.cool/blog/2017-05-16-introducing-a-cli-fun...