1) Which Avengers are represented (I know the name on the tin says current Avengers, but that could still be a long list).
2) The next question SHOULD be which members of the JLA is Amazo manifesting? Because it could be Superman, WW and Flash ....or it could be Supes, WW, Flash, GL, Firestorm, Captain Atom, Meera, Zatanna, Vixen, Supergirl, Martian Manhunter, Lobo ....you get my point ...
I say this because an Amazo manifesting all the powers of the JLA would be something ...terrifying. In fact, manifesting ONE power set from the some of the more powerful members of the JLA could defeat MOST (not all) iterations of the Avengers.
Manifesting all of them ....Amazo really wouldn’t have to mimic anyone from the Avengers if he’s bringing full JLA currency.
Since no version specified, assuming Amazo that's copied the entire Legion of Superheroes.
Amazo wins.
__________________ What CDTM believes;
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.
Giving this to Amazo since he still possess Flash powers and was using them pretty effectively when he fought the JLA. Without it, im going with the Avengers.