If it increases your productivity up to 300%, that means that you can work for 5 months, then take a month off. You will still get ~30 months worth of work done in a year. So thats a huge success.
I love how he says "I find it utterly annoying when any fanboy makes broad claims such as 'Developers are Switching to Mac'"
then goes on to say..
"Windows sucks. Period."
I've played with Macs, and have given Linux an honest shot, using it as my only OS for about 2 months. I am simply more productive developing PHP/MySQL on windows.