[jshen]

it's just a stripped down version of intellij, at a lower price. Pay for intellij and you get all the languages that are supported.

[EdwardDiego]

PHPStorm is more focused and coherent and includes some features that IDEA + PHP plugin doesn't, IMO. If I were a full-time PHP developer, I'd use PHPStorm, but for my occasional PHP needs, IDEA + PHP plugin is ideal.

PyCharm is much the same - for full-time Python development, I'd prefer it to IDEA + plugin.