I see lots of people praising the calligraphy tool in Inkscape, like these guys. That tool is essentially the one that lets you draw as if you were holding some kind of pen or a brush. It's pressure-sensitive so it generates more or less realistic and 'alive' strokes.
On the other hand, the pencil tool generates just plain bezier lines that you can bend and modify afterwards. It follows your trace and kind of approximates what you are trying to do. After drawing a stroke, you can modify it quite easily, whilst the calligraphy tool generates strokes that contain so many nodes that it's not worth trying to rearrange it, it's just better to redraw that particular stroke.
Right now most things you see in my comics are drawn using the pencil tool. That's why they have a clear-line look. I like how it looks, although it's quite a lot of work. I sometimes scan hand-drawn drafts but now I've started doing those drafts on screen using the calligraphy tool and then creating the final version with the pencil tool. I should be brave and start using the calligraphy tool for the final result, but I somehow feel more comfortable with the pencil approach, right now. Incidentally, the calligraphy tool is very sensitive to zoom so if I zoom in the strokes become thinner. It's a bit weird there might be some way to avoid it but right now I can't seem to find it.
Here's a sample draft with the calligraphy tool. It just takes a minute to draw something like this:
I like the simple appearance. On the other hand, here's an image first drafted with calligraphy and then redrawn using the pencil tool:
The second drawing took a little longer to draw, but it's still only a few minutes. The difference lies in doing further modifications: I can now tweak, shade and otherwise work with this image in a way that is simply not possible with the calligraphy approach.
I think I'll continue using the pencil for a while but I'm going to experiment on separate comics with the calligraphy tool.