Whenever I hear "the new PHP" or "its not the old mess anymore", I say to myself, thats hardly the point. The key flaw I find with PHP is with its community and lack of any mature frameworks. Half of the PHP coders are hopeless script kiddies, thanks to low barrier entry it has, and I don't feel a single framework exists that can match Rails or Django. For the matter of fact, the framework with largest community, Codeigniter, only has inline test functions for any kind of testing and doesn't even come with a auth library.
Being a PHP developer myself, I can't refute that only selling point of PHP, albeit, a major one, is its so "easy" to get things done. I feel in the near future, with advent of tools to make mature frameworks more accessible, PHP would cease to be a tool for any serious web development.
..and I'm only listing the more popular frameworks that I know of that are mature.
Every single one of these has full unit test coverage, and most have very clear examples of how to unit test your code.
I like that I can pick from so many frameworks instead. This allows me to choose a framework that fits my problem, instead of fitting a framework around my problem. I find this to be one of the highlights of the PHP community, not one of the downfalls.
That question depends on what your trying to accomplish.
If you're operating on a massive enterprise scale, it's probably not going to be good enough for your hardware. The HipHop VM might be a saving grace if you're already built on PHP, but pragmatically it's probably a better idea to choose a more matured solution (probably something on the JVM).
If you're doing something that is algorithmically intensive (video encoding as an arbitrary example) PHP is going to be a bad fit.
However, if you, like the vast majority of developers, are working on a website that's main technical purpose is to store data of some sort to a back end and retrieve it later for display and you're not yet operating on a large scale (1M+ users) then PHP itself is probably not going to be your bottleneck for a long time.
If you're a fan of benchmarking, techempower does a good job of unbiased comparisons (although keep in mind these are just benchmarks. It doesn't account for how a particular language or framework is optimized for):
http://www.techempower.com/benchmarks/
Performance isn't bad. You've been able to install an opcode cache for years, and there's one built into the runtime now. HHVM really boosts performance, and it's closing in on full compatibility with mainstream PHP.
The most problem application is IO speed.
While testing php speed,problem speed occur on include,require file.Each include toll 200 to 300 ms. If you build your server with SSD .It cut short the io issue.Don't overlook some micro optimization tips..
I find it hard to believe you're a PHP developer and believe Codeigniter has the largest community. Perhaps you primarily used PHP 3-5 years ago.
If you haven't been following Laravel 4 development, you're entirely missing out on a community that's bringing the love back to PHP.
The core PHP community is extremely knowledgable; you're just not interacting with the proper subset. If you take a look at the conference circuit, you'll see a group of passionate and experienced developers willing to share their knowledge.
Check out some of the works pointing the general populous in the right direction:
Codeigniter has been all but abandoned by EllisLab, the community is giving up on it and there are far better frameworks available now. For example Laravel, the growth that Laravel is experiencing right now is huge, it has overtaken Codeigniter as the most popular PHP framework on GitHub and has a growing and active community. Anyone even thinking about Codeigniter any more is doing themselves a disservice, Laravel is leaps and bounds ahead of Codeigniter. Laravel is on its way to being the Rails of PHP.
I recommend FuelPHP [1] - it has amazing documentation, a lot of built-in libraries, takes advantage of PHP5 features, is quite mature and really easy to dive in.
Sorry, but this is mostly wrong. PHP has two awesome frameworks - Symfony and Laravel. They both have their pro's and con's, but both are very mature frameworks that can both match Rails or Django in their own rights. Both of fully tested, both have full auth libraries.
CodeIgniter does not have the largest community by any stretch, and its falling fast. If it hasn't already died, then it will in the near future.
Sorry, but based on your comment I don't think that you really know much about the PHP framework landscape.
> The key flaw I find with PHP is with its community and lack of any mature frameworks.
The key flaw in the PHP community are people like you. People who still think that Codeigniter is THE PHP framework (it hasn't been for at least 3 years) yet still have the nerve to look down on newbie programmers.
Why are you being so hostile? First of all the PHP framework world is deeply fragmented and its tough to guess which is getting large piece and yes codeigniter is still a popular choice [http://php.dzone.com/articles/top-5-php-frameworks].
An year or two before the trend was all 'yii' which I though could be 'one framework to rule them all' but after that comes laravel and yet more fragmentation. Yes, I shouldn't ignore that how nice they are but the problem which I see is always the community and with a new one every year, it ain't helping.
Why isn't that the most important selling point of most languages?
The cases where PHP is not appropriate seems to often be known before going into it (with notable exceptions like Facebook of course) but thats a success problem not a fundamental problem with PHP.
In 95% of the cases PHP seems to be exactly the best possible, easiest to get up and running, versatile for web based programming.
I agree on the point of frameworks. I don't like any that exist so I made my own Rails-inspired one. Unfortunately this means I prefer not to do consulting jobs in PHP because it's considered bad practice to use a framework that no one else knows.
(Mine has dynamic ORM (reads db schema), a console (REPL that loads project config and autoloader file), and similar project layout. Recently added REST API system that generates MD and HTML documentation at /path/to/project/help/.)
Anyway, I would say the main selling point is ubiquity. Every cheap host I've seen people (clients and semi-technical friends) use supports PHP. It often takes more work to get a Ruby project running on those hosts. Or worse for a Node project.
I'm not sure if PHP will ever really "go away", for the same reason bicycles won't "go away" just because motorcycles exist. PHP is insanely easy to start using, and while maybe the average person isn't capable of getting it up to highway speeds, not everyone needs highway speeds.
Being a PHP developer myself, I can't refute that only selling point of PHP, albeit, a major one, is its so "easy" to get things done. I feel in the near future, with advent of tools to make mature frameworks more accessible, PHP would cease to be a tool for any serious web development.