These actions are really so close it is scary. The biggest difference is the model number. That said, I believe there was some minor changes to the bolt design to make them less expensive to make. May be some other minor changes too, but a 721/722 will fit in a 700 ADL stock just fine if you inlet the barrel channel to clear the rear sight swell.
The 700's generally are better looking, but they are not better shooting. No need to trade in or sell a 721/722 for a 700 just for the looks if you are going to use if for what it was made for.
EJ