After posting Why I don't like WebDAV, part 1 I got involved in a bit of email discussion with some people who are much more expert than I regarding the protocol (Kevin, Mike, Julian, Tim). I appreciate they included me, and I now know a lot more about WebDAV than I did before.
The protocol itself doesn't really suck. Rather, it's the implementations and the purposes for which it has been used, it seems. It's a bit odd in that it's a lower-level protocol for a high-level purpose. Use it for the wrong purpose, and it's like using the wrong tool.