Hold it! The competition is advertising on *my* list now? Hah, never mind, CL-RDBMS is a nice system, but to answer your question about
oh, come on, they are not competitiors, or maybe a little bit but they are all opensource after all... :) i'm just trying to get people's attention to cl-perec to consider patching it instead of reimplementing it.
seriously, all the three projects have different goals, although all of them are in the db/persistency category. cl-rdbms is even using the wire-protocol part of Postmodern in the postgres backend.
but either way, sorry for the adv. i'm usually advertising the alternatives to my own projects, too. more information is always a net win.