After writing a custom CalDAV server I agree with the author. The number of requests it takes to get the data you need is insane, and most requests will involve

After writing a custom CalDAV server I agree with the author. The number of requests it takes to get the data you need is insane, and most requests will involve a DB hit. My CalDAV server is much more "chatty" than my web server even though they serve essentially the same information. Plus each CalDAV client does things a little differently so it's very hard to debug, especially when most clients are black boxes. Permissions and feature and how they respond...a potentially different. I (unfortunately) consider the custom CalDAV server I wrote to be a bit a technical achievement, even though I'd rather I didn't have to do it. But I had to do it because there's really no other good option for writing calendar services that work with native calendar applications.