I've been playing around with it a lot lately and I love the program. Right now, I'm using the free version to create graphics for Facebook to promote the release of my next novel, The Courtesan's Book of Secrets.
The program is one of the easiest photo editing ones I've ever used, and there is a lot that can be done with it. Also, the site offers great tutorials on all its features. I used the tutorial to figure out how to overlay one photo on top of another. The program also offers templates so you can create Facebook banners and other items. I'm no graphics whiz yet, but the more I play around with the program, the better I'm getting.
The free version is great. It does what I want it to do and I don't mind the little ads at the bottom. In the future, as I get more comfortable with the program I may upgrade and pay, but for now the free version works well. I'm having fun using it to create title pictures for blog posts and fun pictures to post on Facebook.
If you haven't checked out PicMonkey, then I suggest you do. It is a lot of fun and a great program.