[daFish]

Originally Posted by Ryan Ashbrook

Any particular reason, aside from overhead, you wouldn't want us to go with XML-RPC?

The overhead from an XML-RPC based API wouldn't be that much, if implemented correctly.

I see it from the client-sides perspective. If I could use REST I wouldn't need to deal with the whole XML-structure. Just pass GET and POST values to the service who are less bytes instead of XML.
Even the authentication of a user can be done easily this way by forcing the API-Key (which is unique to the user) to be an GET-parameter in each request.

I know there is a lot of academic flavor in this discussion but I made good results using REST-based APIs (I even work with one on an custom CMS the company I work for is developing).