I used to use Chicken of the VNC about 3 or 4 years ago - seemed fine for my needs back then.
These days I don't bother because I rarely need to use a graphical application on my Linux systems. On the rare occasions I do, I just start X11 on my Mac, open an SSH terminal to my Linux box with X forwarding, then open individual applications using X Windows. (This only works because I don't care about state: this would be inappropriate if you want to start an application at work, then go home and use the application in the same state it was at work, then later go back to work and see it in the same state).
Thanks. I will try out the Chicken of the VNC
I checked out the Screen Sharing app. I presume you are referring to System Preferences->Sharing->Screen sharing
I could not find anything which would let me connect from my Mac to my Ubuntu. All I found was stuff which would allow to connect to my Mac from other machines.
Are we talking about the same thing or did I neglect something basic.