As soon as Qnext becomes available for MacOS, I'll try to make it work across the net between my Windows machine and a friend's Macintosh.
In the meantime, I'm testing it between Linux and Windows... After opening 3 ports on my home firewall, using the documentation, I was able to connect two users across a corporate firewall, so that's good.
So far, I tried IM and file transfer. Stay tuned.