No one can answer that except for yourself and only if you have heard each speaker.
My M80V2's are 5 years old and love the way they sound. I don't think I need to spend an extra $6.00 yet alone $600.00 to imporve their sound.
So for me, I would probably go with the used V2's and enjoy a fantastic speaker at a fantastic price, then take the saved $600 and put it towards a VP180 or 2nd sub or... you get the idea.
It's your money and your choice!
Axiom M80, VP180, Qs8, EP500