Scifi, It used to be that 7XXX series aluminum wasn't the best to use on a bike frame because of it's brittleness compared to 6061T6, but that changed over the last 25 years or so. I think it was Reynolds who engineered the first really good 7XXX tubeset, IIRC.
I have an aluminum touring bike and I don't give it's material a second thought. Enjoy whichever you choose.
Brad