In the context of this discussion, GIMP wins. You (or a group of users) are "free" to create an alternative interface for GIMP. The rest of the features of GIMP are readily available to be integrated.

The GP on the other hand is forced to use the exact same interface that Adobe prescribes for Photoshop. Moreover, if Adobe shuts down tomorrow, it is the end of the road for Photoshop development.