What do you dislike about Berkeley DB? I've been using it for a little while for a pet project, and it seems decent. I'd like it to support range-based join cursors, but that's not a major complaint. Granted, I haven't yet had to deal with database recovery, so I don't know how it stacks up there.

Also --- what do you plan to replace it with? I know that AllegroCache started out based on BDB, and ended up not using it. The Franz guys said performance wasn't up to par, and I always wished for more details.