On the whole, I think Teela is smarter than Louis.

Teela looks at the image of the Ringworld - she interprets it as a huge spacecraft, which is wrong but not a bad conclusion.

Teela does the math in her head to estimate the thickness of the Ring.

Teela recognizes what the radiator fins are.

After the ship is blasted, Teela is able to tell Louis how long the ship was in stasis, when he couldn't figure it out immediately.