Okay, well I guess you might be interested to know that @Mail actually approached RC about being "purchased" and using RC as the base for their open source project. Something the dev community said no to (for good reason).
@Mail may be more mature just because they have the corporate backend which pays their developers for the time spent. Plus, their @Mail proprietary software is just an extension of the open source. So they are paying devs to work on the open source, with the exception of some extensions. So they have a huge leg-up there.
I still prefer RC, as I know that it started open source, and it won't just disappear or become a "nominal fee" later on. I will take slow but steady development over rushed and money pushed development.
But it's my preference, and competition is good. But I still like RC over @Mail. And yes, I've used both
As for the "2 years for a production release".... 6 developers total, in their free time. A huge community asking for features, and the devs trying to get a basic code-base done. If you look, @Mail didn't release a beta or anything. They got a base code out (well, a modified proprietary base code). RC wanted to get something out and get feedback. So they had some betas. I commend RC for releasing early to give everyone a chance to "craft" it to be something better. I can't really say that @Mail will really listen to their community.
Anyway.... enough of my tirade...