Seems to work great!
My Jabber / XMPP server is Mountain Lion server (10.8.4) with the "Messages" service enabled. I have it configured to use a registered domain name and am using a self-signed SSL certificate on port 5223 ("Legacy SSL" is checked in my account settings).
Connecting was easy and very similar to iChat / Messages on the Mac.
The user interface is very clean compared to some other Jabber clients Ive tried. To me, a nice interface is usually a good indication of good code underneath. I havent experienced any crashes or things that make me scratch my head.
I like that I dont have to connect to an additional chat service (like Trillion) just to connect to my own server.
I might be missing it, but Id like more control over what happens when I close the app. It seems like closing JabberB only sets my status to "Idle" (as seen from a Messages buddy list). Id like the option to just go offline.
Definitely worth three bucks, and Ill be recommending this app for our employees. Good work!
TheRealHazMatt about
JabberB - BeejiveIM for Jabber