Earlier quoted context omitted.
The interesting thing to ask should be if Facebook or Wikipedia's engineers would use PHP if they had to start from scratch. I used PHP for a big project before for legacy reasons but I wouldn't choose it for anything new even with a machine gun pointed to my manly parts. Neither would I use Java or VB for that matter.
Pretty sure they would agree. The Quora and Asana founders seized on the opportunity to leave it behind, and what I've heard from Facebook staff is that they've managed to live with PHP. I can't remember anyone saying they like it. http://www.quora.com/Quora-Infrastructure/Why-did-Quora-choo...
Taken directly from the horse's mouth, handwavy arguments about languages making no difference to the contrary.