If you are primarily working with just PHP (well most of the time), PHPStorm is the best choice. It has some of the best debugging features you'll ever encounte

If you are primarily working with just PHP (well most of the time), PHPStorm is the best choice. It has some of the best debugging features you'll ever encounter (I originally came from Eclipse) and the Syntax highlighting is second to none. The great thing about what PHPStorm also does is you can see where everything is, hovering over a function or anything documented for that matter will show the documentation for said function. For Wordpress development especially it's really useful. The reason I moved to Sublime is I no longer primarily work with just PHP any more. Javascript, HTML, Python, Ruby, Node.js and CSS are some of the languages I find myself in. Sublime lacks a lot of nice features that PHPStorm has and definitely is a bit more manual in some aspects, I do miss the intelligent syntax highlighting and checking (warning you if you forgot to close a if statement and whatnot).