This thread will be a poll based tournament, narrowing down 48 acclaimed Marvel stories into just three, after which point those three will be pitted against the 3 best DC Stories.
I will post a match up, and you will have 7 days to vote for which story you prefer. It's a structure similar to Wall Crawlers Best Thor Story thread.
Our first match will be
The Eternals Saga (Thor #283-301)
vs.
Ultron Unlimited (Avengers #19-22)