Similarly good experiences with setting up custom recipes that don't use the built in 'App' stack (which provides Rails, Node, and some others).

I was able to go from the 'tinkering at 2am' level of ruby experience to making Chef do my bidding in setting up alternative apt-repos, deploying config files, etc in a day or two.

My one gripe, as with the rest of AWS, is that they seem more interested in MySQL than Postgres. The opsworks cookbook repo has an included mysql cookbook as well as a preconfigured "App" layer, nothing for Postgres besides forum responses to go the DIY route.