I agree with your point about creating different game mechanics. After browsing through both sites and watching the videos, it seems that GamePress is much better in that regard.
iPad only. We found that making games on an iPhone is just not fun with our current interface. We currently don't have the resources to come up with a new interface for iPhone.
We do hope to have a player available for iPhone eventually, but right now our main focus is iPad.
We do hope to have a player available for iPhone eventually, but right now our main focus is iPad.