I'm currently using Brackets for a couple of things:
1. editing config files. I should have set up virtual hosts, but I haven't yet ... one more thing on a long list of todo items! Anyway - I don't like opening them in my IDE while I've got an open project. I don't like digging through folder structures and using open with. When you use the wampServer taskbar thingie to open them it uses notepad regardless of the system default - and it's basically a one line mess.
Brackets fixes this a few ways - it has a context menu item for "open with Brackets" (which you can disable when you install it, but its nice ...) and it remembers last opened files - so I can open Brackets, and pick from a list of recently opened files, which are all of my config files.
2. one-off items I'm working on that I don't want to add to my current opened project in my IDE.
It's a decent text editor, my only problem with it is that if you use it's "open file" it doesn't remember the last folder you opened something from.
I've heard very good things about Sublime. It's highly rated and a lot of people use it. I haven't personally tried it, since I need a full blown IDE, not just an awesome text editor.
http://www.sitepoint.com/best-php-ide-2014-survey-results/
I use PHPStorm, and before that I was using NetBeans. NetBeans gave me a good IDE for PHP development for FREE!!! I didn't try Sublime because it's $70, while PHPStorm is $99 - a few extra bucks is well worth having a full featured IDE.
The only reason I tried it, is because I had some issue with NetBeans - if you google how to do this or that in NetBeans, it can be frustrating, because the examples are often bass ackwards or overly basic, and the videos on how to do things often are an Indian or Pakistani accent or something and I have a hard time understanding them. These are often the videos covering the more advanced features I need, and often the best ones - so it's doubly frustrating when I have to watch it 10 times to get the picture.
I think the issue I was having had to do with filewatchers for sass, or git functions or something. They do work - and it's actually easier to set up than PHPStorm. It might have had a syntax highlighting issue at the time I don't remember. It was a minor nuisance whatever it was, but it bugged me
I tried Eclipse with plugins for PHP years ago and I HATED it. Everything about it seemed wrong.
I've also used some other ones that were pretty good, but nothing I've used stacks up to PHPStorm IF you have the patience to configure it to your liking. If not, or you need a free solution, NetBeans is where it's at!
Here's a comparison - note, PHPStorm also has a lot of NetBeans pro's that just aren't listed. I haven't found one thing it doesn't have that NetBeans does.
http://www.slant.co/topics/253/compare/~phpstorm_vs_netbeans_vs_sublime-text