hey everyone,
i have an ipad already, but do not have an iphone. i was curious how close the hardware is.
would it be reliable to export out for iphone, install on my ipad, and know the playback rate will be about the same?
Well, iPad and iPhone 4 are pretty close, you better get an iPod or something but yes, it is safe…
But take these in account, iPhone 4 is a 2:3 device and iPad is a 3:4 so you’ll have more parts of the screen on the sides of the iPhone as it is wider! I’m not sure about the Unity3D’s default render matrix but I guess that’s how it should treat it, but it is possible that you loose the top and bottom parts instead!
You could simply try a 3:2 and 4:3 ratio in your project to be sure 
Regards