Well, I use oauth only for authentication (IE, use it to get a trusted email address for the web user of my app), not authorization. Of all the systems I've used, kerberos has been the best authn solution, then basic auth to log in as a user where authorization is done in another ACL system (FS acls, for example).
My complaints are almost entirely about the ergonomics of writing oauth code in a server, provisioning the resources to make it work (like DNS), and then debugging 900 redirect_uri errors.
My complaints are almost entirely about the ergonomics of writing oauth code in a server, provisioning the resources to make it work (like DNS), and then debugging 900 redirect_uri errors.