I have never used GIMP, but many of you who have took the time to email me to tell me just how powerful it is and how much you love it.
So here are two reviews done by those in the know, they are in depth and will certainly help you in your decision making process.
Here is what KillerSites.com had to say:
"GIMP is incredibly customizable... In fact, this is where it may actually surpass Photoshop... Definitely try GIMP if you’re looking for something new (or something free) to edit your photos. The functionality and customization options are great for a free program although the multiple-window interface could take some getting used to."
You can read the full KillerSites.com review here.
And this is from the review done by the tech site Ars Technica:
"It's clear that GIMP has a long, solid future ahead of it, and is already really impressive. If you don't have the budget for Photoshop and don't want to settle for a dumbed-down app, then bring out GIMP. It won't let you down."
The full (and extensive) review done by Ars Technica can be found here.
If you are familiar with the Photoshop interface, you can make GIMP emulate the look of Photoshop with GIMPshop.
And just a couple more resources to throw at you before calling it a day, you can find GIMP documentation here, and tutorials here, here, and here.
Here are a few screen shots, click on any to view larger and in a new window.