Not many. . . looking at the specs of the 3700m puts it right at or above the 9800m GTX. But I already agree that the extra cost for a theoretical performance boost is woefully ill advised.
Then again, I do have a sentimental spot for workstation class cards. . . my other laptop has a FireGL T2.
It's all in the drivers and what games are used. The Drivers for the Quadro cards are optimized for OpenGL applications so any game that uses that will run well, if it uses DirectX though it's in trouble.
Tom's did a review comparing a WidowPC Sting with a 7950GTX to a Rock Direct laptop with the Quadro equivalent. They traded blows when the games were OpenGL, but the Quadro got trashed in DX games.