I haven't seen/found what the offer will be for existing C5 users to upgrade, but I will be watching that closely, as some day there will be an upgrade from C6 to C7/C8 etc. and that will be a "selling point" for me to upgrade it then.

The consensus for C5 existing users upgrading to C6, is that it will be a nice upgrade price. I can't see it being much more than the introductory sale price has now, or their DL servers would overload with current users trying for the sales, lol. Im just guessing though.