I found the cheat sheet annoying. Doing all requests over GET is not acceptable, especially deletes. The jury is still out on GET/POST vs GET/POST/PUT/DELETE. I don't see any problem with file extensions. After all, that's how the web has worked from the very beginning. Hard to do discovery without any guidance on format. Version numbers are not very RESTful and I don't care for them. Spend a little extra design energy to avoid the need for versioning. Static URLs are sort of necessary absent better discovery mechanisms. He skips the notion of returning a resource address as a "Location" upon creation.
Annoying or not, its a fairly accurate description of the state of APIs. I agree about the all GET setup, although I've never actually seen that in the wild (seems pretty dangerous). I personally have no problem with using POST for all endpoints with side effects, though opinions certainly differ there.
