Convenient, central app admin.
Can use iTunes gift cards.
Subscription pricing - with access to many more top tier apps included.
Bug fixes and new features will be available here first.
Discounts are possible (volume, education etc.)
More money goes direct to the developer :-)
A few other points worth considering:
- Functionality-wise, the apps are identical
- All apps support iCloud 'syncing'.
- Purchasing direct from this website is safe, secure and handled by Fastspring.com (as used by Adobe, Smith Micro and Smile-TextExpander amongst others.)
- Updates to the app are handled automatically regardless of the way it is purchased.
- All license schemes allow the app to be installed on multiple computers (so long as only one person is using it at any one time.)