If you asked me two years ago what my primary dev environment was, I'd safely say Visual Studio. Even still, I consider it a Cadillac of development environments.
As my needs shifted, I soon found myself in the ranks of a Sublime Text user. It's everything you want in a text editor and then more. There isn't a ton of fluff getting in your way. Since I've been working with node.js for 80% of my time, it made sense to start separating myself from Visual Studio.
I've been aware of the Brackets project since it was announced a while back, but I only gave it a passing glance. Two months ago, I installed their latest sprint and decided to take it for a test run with a couple of Winsitter bugs I needed to fix.
I don't have many extensions installed. I use Brackets Git, which adds a quick way to see which branch I'm in for a repo, and also provides a way to quickly change the branch I'm in. Awesome stuff when you're normally jumping back and forth between the app and the command line.
Brackets has a great live preview mode where it'll run a web server in the background for you, load your page, and reload it as you work on the content. Again, Grunt takes care of this for me, so it's a not-often used feature.
The experience of using Brackets is really nice. I've only had a couple minor hiccups. For example, I accidentally opened a 30 meg text file and Brackets crapped itself. Oh well, so did Sublime.
Oh yeah, autocomplete. As you type, it predicts what you want. In normal editors, you can press TAB to accept the autocomplete. In Brackets, you press ENTER. Annoying as heck, and I had to install an extension that fixed it. I guess if I really cared, I'd submit a pull request.
That's right. Totally open sourced.
What's my verdict? It's definitely worth your time to download and install. The sprint cycle is quick (every couple weeks), so you'll be looking at an update sooner than later. If you don't like it today, come back in a month and see what's changed.