I use VNC extensively, but mostly within the confines of my local network (intranet), and therefore I don't use encryption (not sure if that would add much in terms of overhead anyway, I suspect not). Works great and plenty fast for my needs. Certainly no worse than LogMeIn or TeamViewer, esp. as an intranet solution. On a rare occasion, I will run VNC over Hamachi for remote access, so I don't use VNC encryption in that case either. Again, seems to run very well for me.