It seems the most sensible way to install software, since it will automatically be upgraded with everything else.
To use the GP's example of Postgres: I care a whole lot more about my data than anyone at Canonical does. It would be a firing offense to trust that Canonical handles a database software and data upgrade correctly.
It's also why you can easily set up your own repo in two stages: one that updates from upstream automatically, so you can test changes, and one that never updates except when you specifically update a package: that's the one that your production runs on.
With proper due diligence on our part I trust the package maintainers to make less mistakes than if I have to do it all by hand :)
I've mainly used mysql and never lost data due to an upgrade (we backup before an upgrade anyway), YMMV of course.
Are you talking about minor-version upgrades, security patches, etc? Or any kind of upgrade? I think there's a big difference.
In the case of minor-version upgrades or security patches, what exactly is apt-get taking away from you?
The only thing holding you back is your own fear.
If you don't want to commit a full machine, try it out in a VirtualBox instance.
Keep in mind it's also possible to run your own apt repositories and have your machines source from those, allowing you to define what specific software runs on your farm, down to the smallest detail.
All in all apt can give you a very flexible setup :)
Btw using Slackware on one server in production and i must admit that small specific systems are perfect match for Slackware (VoIP, routers, ...). And ofc non-production systems (laptops, testing and development environments, etc).
with ubuntu, there is too much majic, i dont run a server, but for example i dont think anyone should install Postgresql sql on running production server by running
slackware i believe would force more discipline, i wonder how reasonably large companies run/admin their servers (do they apt-get everything)that would definitely be a nice book to read, someone should write it