I think it's a great program, especially since it's free. It's definitely at least worth trying. I haven't used it for "vectoring" images, but it really helps for doing drawings such as this. At least it makes it a bit easier than it would be in gimp, because the calligraphy tool in inkscape has a setting called "mass" that makes it easier to draw with a mouse, which is great since I don't have a tablet. Thanks guys.
I haven't really used photoshop before, so I wouldn't know. But if the pen tool in PS is at all like the paths tool in gimp, then it might be a little easier than in inkscape. I don't really use inkscape for "pentool" though. I use it to draw because what the mass setting does is it makes the calligraphy tool lag a little behind the mouse when you draw, and that helps smooth out lines when I draw, which is great because otherwise they would be kinda jittery since it's difficult to draw very steadily with a mouse. That's why I drew spidey in inkscape, but I made the background in gimp because the paths tool worked a little easier for that. Seriously though, it doesn't take long at all to download and install the program, and it's free, so you might as well try it out for yourself. I found inkscape to be a very good free program that was easy to pick up, but I've heard other people say it's hard to use, so you may not like it, but I guess you won't really no for sure unless you try it for yourself. Plus, it comes with a couple tutorials that really help explain the basics.