I used to play Cyberboard games a lot. I still do for card-driven wargames. For online play I prefer ZunTzu. Mostly my own gamemodules (see files section).
Unfortunately I cannot seem to play anymore (see technical forum) so that's a real shame...
My group overwhelmingly prefers ZunTzu, and only resorts to Vassal when ZunTzu cannot support the chosen game due to a technical limitation. (we are patiently waiting for ZunTzu 2.0 to fix that) We don't use Cyberboard at all because we play real time.
I am pretty new to Zun Tsu, but I mostly play solo games. It is convenient for playing on the road where it is not possible for me to take my physical game boxes. If I could talk friends in to playing hex and counter war games a little more often, we will probably try to do so with Zun Tsu.