How stable is Geronimo?

[Stefan Arentz]

This might be an odd question for a project that is still highly under 
development but I am preparing for the future here and I would like to 
do some experiments already. I am just trying to figure out if this is 
already the right time to do that.

How stable is Geronimo at the moment? I am mainly interested in a JMX 
core/kernel to build some of my own services on and a Servlet container 
to run simple web apps in. (Spring powered) Complete J2EE architecture 
is not very important.

 Stefan