In this new post to his blog Stefan Koopmanschap looks at a plugin for the symfony framework that has him impressed.
Using this plugin, it is not necessary anymore to really care about which ORM you pick for your project. It's the thought behind symfony 1.1 taken into the symfony ORM-selection.
He points to the DbFinderPlugin as an alternative to rewriting up the ORM code for your application by hand (or in something like Propel or Doctrine). It makes switching between ORM layers simple - just a configuration change to point to the new system.