Forgetting about the cheating controversy for a moment ........ (unless you want to contrast the rather mild controversy of the Dolphins being penalized a draft pick for signing Shula away drom the Colts, in comparison to the huge controversy that spygate sparked - and also resulted in the loss of a draft pick.)
Undefeated regular seasons
Considered best team of that era
Future hall of fame quarterbacks
If not for spygate I would say future hall of fame coaches too, but that is certainly not a given any longer.
Top defense in the league versus top offense in the league.
Running offense of Csonka - Morris - Kiick to passing offense of Moss - Welker - Stallworth.
Dolphins seal the deal in the SB, Patriots don't.
Dolphins were revered, Patriots were vilified.
There's probably a lot more, but that should get you headed in the right direction. Like FinFrenzy said, check stats and maybe a site like Pro-Football-Reference.com for how they compared and ranked.