Payton worked with Romo as assistant head coach with the Cowboys when the quarterback arrived undrafted from Eastern Illinois 10 years ago.
Romo has racked up over 2,500 throwing yards and 20 touchdowns already this season, leading his side to the top of the NFC East.
"He's having, I think, the best year of his career this season, right now," Payton is quoted as saying on Cowboys.com. "Just having a chance to watch three games myself on that side of the ball, he's been very good in regards to his decision making.
"Tony knows pre-snap where he wants to go. He's got a very quick way of getting through his progressions and the ball comes out extremely fast.
"His ability to move and extend plays and avoid pressure and avoid sacks has served him very well. So I think from a decision-making standpoint, each year you're seeing someone who's becoming more comfortable in the system."
The Saints host the Cowboys this weekend, with both sides looking to improve on their winning records so far.