I am here to join Gimp's side. I have found Gimp easier and more effective than photoshop, especially when rendering. The one downside is the lack of some built-in patterns that PS people love so dearly, but those can be easily implemented into Gimp due to its awesome ability to be modded. (another perk over PS, since its freeeee)
and drsynyster, that's a mac/PC analogy.