True, Chef and Puppet kind of take the pain away between different linux distributions (which is good). But this would be aiming at a deployment.
However, one common use case (for me) is having to have a one-off install, which unfortunately kind of prevents that.
If my job needed frequently installs of DBs I would have probably gone this way, but it isn't, so today it's PostgreSQL 9.1 on Mac OS, tomorrow (more likely, a year or two from now) it's MySQL on Fedora, etc
Chef and Puppet can deploy just fine into a development machine - either a VM (i'd recommend this) or even on your host machine. I can't imagine any workload that's simple enough to be handled by a vanilla, untuned mysql instance and at the same time not simple enough to be handled by a scripted postgres installation. Things get different once you're getting to more complex workloads, but the effort of tuning a mysql instance to handle those is in the same ballpark as the effort of tuning a postgres instance.
However, one common use case (for me) is having to have a one-off install, which unfortunately kind of prevents that.
If my job needed frequently installs of DBs I would have probably gone this way, but it isn't, so today it's PostgreSQL 9.1 on Mac OS, tomorrow (more likely, a year or two from now) it's MySQL on Fedora, etc