Yeah my site is more social-oriented so I can see how your site may work better with something like mongo (if it's mainly lat/long coordinates). Just as a quick example of something I ran into: When saving comments I liked to save the user's _id, username, along with their avatar so I wouldn't have to do a join later on, but then realized what if the user changes their avatar? Since I store the avatar as a row in the `users` collection, then I'd still need to do one of those nasty fake joins.

The post/pre-save methods are pretty bad ass and there are a few things I still do like about mongo (which is why I chose to explore it initially), but I think for social type websites, a sql solution makes more sense. I also scoped @ http://www.rethinkdb.com/ which looked interesting, but at this time I wanted to go with a more bulletproof solution to my problems.