I've had harsh words to say about Atom in the past, but that was mostly over the feed format. I haven't looked at the posting API yet - maybe I should. The Blogger API and the MetaWebLog API are simply nightmares. There doesn't seem to be any standard way for client tools to interact with a server - I was debugging the interaction between a client and my server last night via IRC. Even better - the client was set to use the MetaWebLog api, but was sending requests to blogger.apiNameHere names. Sheesh. There was also an interesting difference in api points - I had implemented 'getUserBlogs', and the client was sending 'getUsersBlogs'. A quick Google search turned up references to both. Sigh.
I implemented both names, pointing to the same method. I had to map blogger names over to MetaWebLog entry points, at least for the tool being tested last night - who knows what oddness will turn up next. What a complete mess...