The first time I got to know Gimp was when I had to draw a demonstration picture for my research paper. I had to combine one piece of picture with the violin architecture in it and another piece of an iPod touch together. My final target was the violin strings placed inside the iPod touch screen bounds. I spent one hour trying to figure out how to do it but resulted in vain. When I was worried like an aunt in the hot pot, one of my friend recommends Gimp to me, as it is a free open-source graphic software which can work on both Mac and Windows systems.
My first impression was that it took a long time for the software to launch, which resembles the occasion when you want to launch Photoshop. After that, the main interface appeared and I found that it consists of three split panels. I was used to the all-in-one integrated interface under Photoshop and felt difficult to take all the three movable panels under control. Besides, I often pressed wrong shortcut keys as some of them are totally different from those under the environment of Photoshop.
However, Gimp still worths our trying, though it is very young and cannot compete with Photoshop in some aspects in a short term. First and foremost, Gimp is free and cross-platform. If you change between different operation systems quite frequently and do not have very high demand on the visual effects of graphics, Gimp should always be your first choice. Also, through my experience, when undertaking the same task, Gimp takes less memory than Photoshop does, which might be a good news for the users running low-level machines.
Why not give it a try. Allow sometime to get used to it and you will find it a tool designed just for you!