The ATP episode where he talked about this was incredibly fascinating. Marco is such a role model to me - he has a complete immunity to fads and trends, and just does things the way he wants to. He adopts the 'new and cool' things only when they have a real benefit.
I largely subscribe to the use boring tech ethos ... but php? come on man.
and yet... successful people have used it to build really successful things: Facebook, Tumblr (I think), the things Marco's been involved with.
I just dunno outside of meta should we really be pushing php with all its flaws? or is it still flawed and I need to update my priors?