One of the best things about the New Age line was that, at the time, Marvel had gone off the rails a bit with many of their top end properties; the FF were missing, I believe, tons of legacy characters had taken over major mantles, etc. And a lot of Marvel fans weren't terribly happy about it.
So DC offered them an alternative. They couldn't make the classic FF, but they gave us the Terrifics, which was spiritually very much along those same lines but still uniquely DC enough to feel like a viable part of the universe. And a lot of those New Age books had really strong hooks, well developed characters and plots, offered something DC often doesn't, and offered something Marvel usually did but wasn't right then.
The New Age line was never going to survive long simply because they were mostly new characters, but Marvel ended up bringing back a lot of the characters the line was remixing and that, I believe, cut New Age's lifespan in half.