Been using Pixlr (a photoshop-like web browser app) for over 5 years now. Here's why.

* It's free

* It loads so much faster, and the interface is in my opinion just as responsive as photoshop.

* It doesn't require 200+ Meg of space on my hard drive

* I can use it wherever, on any computer that has an internet connection.

* And it has all the features I need in a photo editing tool.

The only drawback for me is that it was flash based and now I found a html5 version and I think I'm in love with Photopea now.