I'm in the same boat. I have 4 microscervices set up with API Gateway + Lambda and now actively guide people away from API Gateway.
If I would have to name one thing, it's that the configuration of API Gateway via the UI is unbearable if you have a nontrivial amount of routes (> 3). I need to configure Authorization, Error code mappings etc. for every route, although they are exactly the same. If there would be per-gateway defaults I can set with per-route overrides, that would cut down the setup time by 95%, which is the main thing holding me back from using API Gateway for projects that would suit it.
Right now the only option I seem to have is using a tool like Terraform to automate it, which is a pain to adopt if you already have a running API Gateway.
Still better than manual clicking in my opinion.
http://docs.aws.amazon.com/apigateway/api-reference/resource...
It gets you to hello lambda (python) in one shot, from the cli. Anything written down in one repo is going to be far more undertstandable than piles of hidden behaviors and obscure error messages. I think there's a new one on their blog for node.