Carmack has been around a long time, and I’ve never heard a word about him that rings true to the PC. Anyone on here worked with him in the past?
All from Carmacks own mouth.
Especially considering that there are two (unrelated) Carmacks: John and Adrian, both cofounders of id software. As for John Romero, he did a lot of "stuff".
Listen to the interview, and see if Carmack sounds like a reasonable boos, able to get the best from his staff, or sounds like someone that would cause serious friction. I'd pick the latter, from his own description of how he treats people.
He's a good programmer. He'd be absolutely terrible to work with or for.