I have just blogged about why we didn't go with OSGi
In a nutshell, I believe the foundations of OSGi are solid but it wasn't built for mass application development. It introduces friction into the development/deploy process that is already fraught with challenges. I'd like to see the OSGi spec leads focus more on the developer/user persona of OSGi to make it invisibile to the development process. Also I'm appalled that the JVM still doesn't have a transparent module standard.
