We did consider not using the tied interface, but wanted to make sure we tested what we would actually be using at work, and I couldn't see people liking the non-tied API. Maybe I'll add that, but it's fairly obvious that it'll only speed things up.

The read-only problem of CDB is frustrating. Though the speed of regenerating the entire DB seems pretty fast, so perhaps it's not so bad for our uses (where we'd be doing rebuilds in a cron job).