Totally agree. Even though I'm a mac user, PC-hostile attitude is a total red flag for me. My experience has been that more Mac-heavy shops tend to be somewhat weaker on the *nix side, primarily because they overlook people with strong Linux chops. If they genuinely know their stuff, PC/Linux people can help you get more mileage out of your infrastructure... which sounds like something 42floors needs at the moment.

There was a story of a failed startup on HN a month or so ago that had a co-founder who stated (jokingly) that they'd no-hire engineers who used Linux as their primary OS. They ultimately folded in part because of technical issues with their infrastructure.

In that respect, it wouldn't surprise me if there's a real correlation between crummy sysops and PC-hostileness in startups.