Here are some comparisons between the 11" MBA with the i7 vs i5. These may not apply at all to the rmbp because of significantly different hardware and fan setup.
I was initially going to go with the i7, then realized that the i5 was more than enough for my needs. If you're doing heavy processing, I'd go i7- the heat difference at most seems manageable. But if you're not doing heavy processing, why not save some $, and (maybe) have longer battery and a cooler computer and go with the i5.