I disagree with the notion that Romo is a top tier QB. He's had moments of excellence, but I wouldn't say he's any better than Cutler.
His contract aside, I don't think anybody thinks Romo is a top tier QB. Most would agree that the top tier consists of Peyton, Rodgers, Brady and Brees. I'd put Romo in the top 10, albeit near the bottom.
As for Romo and Cutler, Romo is definitely better. Since Cutler's first full season as a starter (2007):
Cutler: 146 touchdowns, 107 INTs, and has a career YPA of 7.2
Romo: 189 touchdowns, 88 INTs, and has a career YPA of 7.8
Even last season, Cutler was outplayed badly by a QB on his own team, as Josh McCown looked far better throwing to those weapons than Cutler did.
It really isn't close.