I have been told this, and therefore never owned a wok, but I'm now thinking of getting a wok anyway because Kenji (aka "J. Kenji Lopez-Alt" of SeriousEats.com) disagrees, and "follow Kenji around like a zombie and taste what he tastes" is a motto that is serving me well in life so far.

Here's Kenji's non-scientific rant on the subject:

http://www.seriouseats.com/2010/06/wok-skills-101-stir-fryin...

Here's the better-equipped-with-charty-graphy-goodness version:

http://www.seriouseats.com/2012/06/the-food-lab-for-the-best...