Glad to hear GKE's working well for you -- thanks hosh and whalesalad!
We do invest a lot in making Google Container Engine a great experience, including integrating it with other parts of GCP (e.g., IAM [1]), but at the same time, the core is plain vanilla Kubernetes.
I don't regret hand-installing Kubernetes on AWS, if only because I know a lot more about how it works now. But I rather just spin it up with GKE.