Corection. It is not a Harp, but indeed a Lyre. The Lyre, used by both Zelda from SS, and Sheik from OoT is a facinating intrument. Being it was passed down from the Goddess Hylia, the power it contains might be limitless. The Ocarina of Time however, is also used my the Royal Princess Zelda. Both have unique super-natural powers and compensate a specific derived magic, usually the ancient Goddess(s) Din, Nayru and Farore.
I think you should've atleast added an option for 'Both' Instruments.
When you make a thread you will get the option to make a poll towards the bottom.
And I liked the ocarina, Simply because you could play any song at any time, the harp you couldn't really pick a song at any time you wanted to play, but if I can throw this in hear I liked Majora's Mask, how you could switch between races and use different instruments, and they would all sound different I loved the drums.
Gotta say Ocarina. Much more variety with the songs and quite honestly I like the songs a lot better for the Ocarina than the Lyre/Harp/whatever you would like to call it. And it's easier to play (...I didn't like playing with Kina very much. Darn customers...).