I use the Gimp 2.6 for all of my work currently. Its more basic than Photoshop, But when you get the hang of it you can get many great effects equal to those, sum even better than those you can get on PS. But its alot harder to get the same effect on the gimp.
When I have used photoshop I cannot seem to get the hang of it. I much prefer using the gimp, it just depends what you have learnt first I guess.