It'll be like the iPhone vs Samsung Omnia
The iphone really gets its purpose, its a mobile device you can jab at with your finger and watch movies, listen to music, take crappy pictures and make calls. You can do all that with the Omnia (except you can take much higher res crappy pictures), except it feels like you're using windows by pushing a mouse with your nose.
Starting an application is a good example - iphone: push the big button with the right icon, move around between pages of apps by swiping at the screen like a deranged ape - omnia: click the start menu, select all programs, double tap the right icon, move around between the different apps by carefully dragging the scroll bar of the app window..
It does the same thing, in much the same manner, with much the same effect, but it doesn't get why it is doing it that way and therefore doesnt get it right. Their app store will be just the same, it will do everything just to spec, but it just wont be as trivial to use as the appstore, and probably wont generate as much revenue.