James Strachan is really liking SCA:
Incidentally ServiceMix and ActiveMQ are moving to Apache too; which coupled with Tuscany, Geronimo and Synapse, its looking like the SOA stack of the future is going to be created at Apache. These are exciting times!
Indeed, assuming you want to end up with a middleware stack that supports more distinct APIs than most applications have classes.
Steve Loughran has some comments on SCA, too …