I have the latest v.3.1 release of Easy Bloggins which does some integration with Pro Sites. So currently subsites that are not part of the Pro Sites pool show the "Upgrade" button (actually labeled as the supersite name).
Two suggestions/feature requests:
1. The Upgrade button should be named as "UPGRADE" rather than the network name. Reasons for this: It is more descriptive of what the action does and it syncs with the name of the button in the regular (non "easy" interface).
2. Display the corresponding "Your Account" button for websites that are part of the Pro Site pool of sites. Per above, use as button label whatever is displayed in the regular interface (non-easy mode).