You guys are funny talking about what you think matters, if you haven't stepped in the ring and got hit or did the hitting you're only guessing. I've never sparred with anybody who used 8 Oz gloves in fact I'm not sure 10 oz either, but I have been popped in head with everything from 12oz to 18oz and it makes a difference to me. I can tell the difference in sparring partners hand speed and pop.
You don't even have to ask the question to be honest just hit the bag three rounds with both and them let us know