Just bought and returned the Mark III invoking consumer protection
An upgrade is supposed to improve a product or is that just a concept? I put my notes here
http://interceptor121.com/2014/07/11/sony-rx100-mark-iii-is-it-worth-upgrading/
Extremely disappointing
Well, at least the LX8 is around the corner, so you might another option 
I hope they offer something more than the fz1000 and also 24/25p high bitrate modes that would be more useful than 4K for me