I ususally work with both models (700 & 500) Probably ccds block is similar, not the same, but 500 comes from 350 medium level cameras. Codecs, bit rate etc are the same but processing aren´t. Menu settings can´t be changed between them.
In a direct HD-SDI output to monitor pictures are very similar, but 700 is in a upper sony level. There have been 10 firmware updates for 700s, and more than a year after 500s started, just one update, and there are not news about others coming. This is very important because 500 needs fine tuning in some areas. (ATW, zebra, etc.)