Hi
I have not been following this thread so not sure what your issues are, but what I can tell you is every theme that provides as many features as Dante will come across many bugs and ‘glitches’, and we do our best to get these solved right away.
Anything to do with installing the demo content is down to your memory limit and your host, not the theme. If it fails when you try installing the demo content then I suggest upgrading your hosting.
You could buy one of the other top selling themes but I guarantee you will come across all of the same problems.
Regards
Kyle