Ehh... for the 9" screen or whatever it is, I would personally go with regular quality. I prefer HD video on bigger screens myself.
Rentals from the iPad cannot be transferred to a computer or another device.
Rentals from the iPad cannot be transferred to a computer or another device. If I were you I would find one of the free tv shows they offer in SD and HD and download both versions. I tried this out with the 30 Rock pilot and The Office pilot, both free of charge.
I've only rented one movie and went HD.