Aikman always suffered detractors because he played in a brilliant team with one of the best running backs in league history. I never thought he was one of the elite passers (he fucking loved an interception and his accuracy in regular season play often veered south of 60%), but he could manage the fuck out of a game, and kept a team of total maniacs on course until it totally ate itself. And he manned up in the playoffs. That pretty much made him elite. He was like the reverse-Romo. Looked alright in regular season play in a great team, then pressed a switch in January (Romo flicks a switch too, but it's the one that opens a trap door beneath him). He'll continue to suffer detractors today because football has changed and the top QBs put up gaudy numbers year after year, which Aikman didn't.
I would say that he was one of the elite quarterbacks of his generation, but he wouldn't appear on my all time list. That might be unfair on someone who has three rings, but he never had to carry that team himself, and you suspect they would have won multiple titles with other QBs. Where as if Smith had been taken out of the side...
Plus, he's a Cowboy and I'm hardwired to hate him.