I've posted a comment to Philip's opinion of PG. It is truly ridiculous to consider Oracle OPS a mainstream product that has any impact on the real, practical use of an Oracle database.
To be fair to the PG guys, btw, they have expressed interest in using OpenACS. They just don't have a whole lot of time to set it up. In particular, they might want to use SDM and bboards. If a few OpenACS community members want to help them out, that would be a great project to take on...