I was under the impression that current Amazo does not absorb abilities and simply has all the powers of McDuffie's JLA. After all, he was using Black Lightning and Red Arrow's abilities against the Flash before any of them showed up and I don't remember him absorbing anybody else's powers. I mean, he might have that ability but he certainly never showed it.
Does current Ultron have an adamantium body? And machine control? Cause if so, I'd vote him over the most recent version of Amazo.