I don't know what businesses other people have collaborated with ... but to me the people behind the products I'm using matter a lot, I'm not dealing with faceless entities.
Personally that's precisely why I'm using Postgresql ... I can talk to the core team of developers and get their input whenever I feel like there's a problem with Postgresql. And for a web service we worked on, we even hired a Mysql developer to come and help us (was also on Sun's payroll at the time).
How could I trust a product based on ZFS or how could I trust them to build my products on top of Java or any of their Sun-derived solutions ... when the top talent that worked on those products left?
Not to mention I don't like hypocrites ... before the Sun acquisition they called on Sun to make the JCP more open. Is this an US thing? Can companies fuck with you because it's just business?
Oracle seems to me like a sweat shop. Nothing wrong with that and I'm glad they are making lots of money ... but in my shop you can get fired for suggesting Oracle products, and it's not just me, there's a whole generation of software developers that won't touch their cash cows.
There's a whole generation of developer that have chosen Mysql or Postgres or implemented their own shit, and did not go for Oracle's DB ... that's revenue and opportunities lost for them, and I'm only seeing this trend getting stronger.