With all the new development toys why would someone want to choose PHP for their next new web project? Why would someone choose PHP over node.js or Rails? It's easy to say something is a legacy application in PHP and it's not cost effective to migrate away from it. It's entirely different to choose something for an entirely new project all together. So, here are 4 reasons to consider PHP for a new web project.
There Are Bodies To Hire
What happens if your project takes off and you need to hire people? Or, you hired someone to develop your site and they are not longer available and you need them? If a project has a need for people choosing a language where there are fresh warm bodies is important. There are a lot of developers with PHP experience. Compare this with Ruby (and Rails) or node.js. While these projects may be younger or hotter how deep is the available talent pool of available developers? I'll give you a hint, it's not deep enough. PHP has a deep pool of developers.
Hosting Is Everywhere
People who know me might say I point this out too much. But, if you are going to create the next product for the long tail of sites or want to try and create the next big CMS you'll want to start with the most fertile ground for hosting. There is a reason PHP is currently used for 77.5% of sites. You can host PHP stuff almost anywhere.
There Are Good Tools Available
This is where I can imagine getting push back. Good tools? Really? It's not like I'm suggesting you build a Wordpress site (16.2% of all sites are wordpress). I'm talking about frameworks like Symfony, dependency managers like Composer, editors like Sublime Text 2, and documentation tools like phpDocumentor 2 or Doxygen. The tools to write good quality code exist in PHP. I'm not joking. Really.
Lots and Lots and Lots of Documentation and Knowledge
Floating around the PHP community and the web there is a lot of documentation on PHP. Has your project grown and it's ready to move off shared hosting or a single VM? The documentation and knowledge for scaling is all over the place.
This even applies to searches. When I search for a programming topic in PHP I tend to get more results (sometimes significantly more results) than the other server side languages I've searched for.
Using PHP might not get you fame and accolades from computer science purists. Or even from cutting edge hackers. But, that hasn't stopped Wikipedia, Facebook, The White House, Etsy, Wordpress, HP, and so many others from being successful using it.