I'm seeing some anomalies with the menubar icon since moving to Mavericks and Tunnelblick 3.4beta (build 3741 at the moment).
Sometimes, but not always, the icon appears all the way to the right --- right of the Notification Center, rather than right of the Spotlight. Sometimes, more rarely, it does not appear at all.
It seems to happen upon first launch --- that is, the first Tunnelblick launch of a particular login session. If I quit and re-launch, the icon inserts itself where it should.
This isn't a major issue for me, since I rarely use the Notification Center and refer to the Tunnelblick menubar icon ONLY to remind me that I am (or am not) connected to a VPN. That said, it's clearly a bug. Otherwise, the beta has been very solid for me, both on the client and the server side. Once in a great while, it'll get into a state where I must quit the client Tunnelblick and kill OpenVPN processes; again, this is a minor annoyance and most likely due to the workstation going to sleep while a session was open, then not reconnecting properly.