Mac OS version is not so easy, isn't it? As it would required rewriting all software from scratch in objective c.
All is up to virtual machine, obvieusly free solutions have more chances to fail and will have same problems with new games, specific software or construct.
Definitely with time there will be free vm which catch up with paid but again why to give away forever descent level software if you can sell it.
I am a Mac user and i have vm fusion 4 with vindows 7. No updats to both. Construct 2 is general working.
Instaling java gave me avability to publish game to html (64bit version - but construct will kindly tell you if you will get an error).
The demo star ship or whatever name is - is not really working, is slow and there is no control but that may be just demo as ghost hunter is working.
My mac is 2008 model so I do not bother now and wating for new one to arrive and will give you update. Also will buy fusion 5 which supposed to make instalation smooth.
The ONLY thing you will miss on Mac without native app is instant preview of html you doing as it need a server. ( in case you want to copy files from windows to mac - which i believe you want - construct suggest coping files to ftp server) But again it's not that bad as apatch is preinstaled and if you switch it in options you can just copy files to websites folder. I will test it too and give an update.
All best
Greg