There is nothing that runs on one Mac that doesn't run on all the others. Apple's device classes are getting confusing, but at least everything in a category has access to the full ecosystem (either iOS or OS X).
There's nothing that runs on current-gen Microsoft hardware that doesn't run on all the others either, with the exception of phones (and Apple has that limitation too). There are no current-gen Windows RT devices.
To continue my other post, you are of course right and I shouldn't have brought up iOS. Running iPhone apps on an iPad is such a kludgy experience that it might as well not work at all. Let's see if Apple manages to make things even worse with the rumoured iPad Pro :|
