In short bursts, but for any prolonged computing, the air will pull ahead due to the active cooling.

I use an air as a development machine, and it works great.

Well, to be fair, any prolonged, heavy computing will also kill the Air's battery. And the fan sounds like a freaking plane taking off.

Shorter battery life vs. significantly reduced computing power (due to reduced heat dissipation). Personally, for the development use case, I'll take the reduced battery life; I can mitigate that problem with a power cable.