When comparing PhpStorm vs IntelliJ IDEA, the Slant community recommends IntelliJ IDEA for most people. In the question“What are the best IDEs?” IntelliJ IDEA is ranked 2nd while PhpStorm is ranked 9th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supports various PHP frameworks
Supports Symfony2 (including Twig and Doctrine), Yii frameworks, and Laravel.
Pro Intelligent code completion
PhpStorm has two types of autocompletion: structural completion and word expansion.
Structural autocompletion makes predictions based on its understanding of PHP, while the latter tries to predict the word currently being typed based on previously typed words. Word expansion also works in comments and docstrings and it's similar to vim's omnicompletion.
Both types of autocompletion work extremely well, have little to no problems and are quite fast even when loading suggestions on the go.
Pro Inspections of all kinds
Not just for PHP, HTML and JavaScript, but especially good is SQL inspection and auto-completion of tables and fields. You can see at a glance, that your DB structure is in sync with your code.
Pro Database view
The database tab, while not perfect, provides all the tools you need for daily usage. You always have your DB overview on the side (you can hide it when not needed).
Pro Plugins allow futureproofing and customization
Active development work on plugins is always a plus, as it can extend the use of the IDE.
Pro Auto-sync with remote folders
It allows monitoring code and sync the files that need to be changed with a remote server. This works more efficiently than libnotify and faster than vagrant auto rsync.
Pro PHPDoc support
PHPDoc is a documentation generator. It allows automatically generating documentation from specifically formatted comments.
Pro Integrated Git GUI support
Allows users to manage their repositories directly from the IDE with a GUI which lets you do all Git commands.
Pro Lots of plugins
Lots of plugins from JetBrains and the community are available, from useful things like support for Docker, Vagrant, Angular, Vue.js and more useless (but fun) like a nyan cat progress bar.
Pro Code Refactoring
Quickly rename classes, methods, and variables used across multiple files in the project.
Pro It comes with Testing RESTful Web Services
Save time of building your own or integrating libraries for testing RESTful Web Services. PHPStorm enables you to test endpoints without leaving your workspace or disrupting your workflow . You can code your endpoints in one window and test it immediately from another window.
Pro Templating support
Supports Twig and Laravel's Blade (among others). Technically the later is part of a framework which Phpstorm supports but I've seen IDEs (e.g. Netbeans) with Laravel support but no blade support so it does deserve a notable mention.
Pro Built-in debugger
Has built in support for Xdebug including remote debugging.
Pro Phar package recognition
Phar support allows running complete applications out of .phar files.
Pro Regular updates for fixes and new features
PhpStorm is clearly being developed continually, which gives confidence that it will be available for some time and is not abandonware.
Pro Zero latency typing
Type codes with pleasure. Delay of visual feedback on a computer display has an important effect on typist's behavior and satisfaction, as cited here.
Pro External command support
Ability to setup custom external commands, which is something inherited from eclipse and found lacking on netbeans.
Pro Has built-in console and SSH clients
This allows execution of needed commands without switching to other windows. It also keeps track of what's happening right in the IDE, which is especially good with Vagrant, because you can connect to a VM in a single click.
Pro Emmet integrated
Pro Integrated Vagrant support
It recognizes Vagrantfile and allows full control from the IDE.
Pro Task/Context functionality
Similar to Eclipse Mylyn: you can create tasks or retrieve them from your ticketing system, and each task keeps its own context (opened files, modifications, etc.).
Pro Responsive core developers
Pro Excellent search tools
Especially the "find in path" feature that displays both results and file preview!
Pro Great Java Support
Pro Great JavaScript support
Pro A good editor for test-driven development
IntelliJ IDEA is really easy to work with when it comes to test-driven development in Java and JavaScript/TypeScript.
Pro Markdown support with preview
Pro Good BASH script support
Pro Great TypeScript support
Really good support for importing classes, libraries, etc. into a typescript class. Making it easy to do TDD.
Pro Supports PHP quite well
Pro Angular CLI support
Cons
Con Resource exhaustive
It often maxes out even 4 cores, not to mention several hundred MBs of RSS with a single small project opened.
Con Pricey
Currently costs £78 but does not seem to offer much more than some free counterparts.
Con Proprietary
It is not free software (free as in freedom).
Con Slow performance
A very slow indexing, many memory leaks, large projects after some time will be very slow, opening large files like 10mb can even break IDE.
Con FTP Extremely Slow
FTP File transfer is extremely slow compared to filezilla or other ftp programs

Con Interface is cluttered
Con Sometimes buggy
Index gets corrupt which results in errors in syntax presentation, code validation and auto-completion. Version-control system sometimes stops working, occasionally freezes in big files

Con Bloated
Con Only one project can be opened at a time (
Con Is not free
But it does have a free version (Community Edition).
Con Heavy
Consumes more resources than VSCode etc. But depending on your use-case, it can still be worth it for the benefits you get with this editor.
Con Autocomplete does not work while IntelliJ is indexing
But this, in general, is not much of an issue. Usually after npm install, etc.
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