I had one of them. They are hard to use since you have to hover instead of actually pressing down on the pad. If it touches the pad it registers as a mouse click. You have to float the pen over the surface without touching to draw a line.

I had such a hard time with it I gave mine away.

@johnpowell
Actually, you only have to hover if you want to move the cursor around without drawing a line.
To draw a line, you do have to touch the pad.

Correct, I mistyped. But it is still hard to get used to at first. But I do think there is accidental clicks that could bounce the cursor around.

Yes, my finding has been that even a correctly working tablet will register shaky lines. It’s just kind of the nature of the beast and takes some learning/getting used to.

You might want to get Manga Studio. It has a stabilising feature that will help you draw straight lines and smooth curves.

Re: ragingloli’s answer, Paint Tool Sai also has a stabiliser, and is my current program of choice for lineart.

On a related note, some artists I know place a sheet of paper over the tablet surface, but have since weaned off the habit. The paper method makes it easier to achieve a straighter line – true – but at the expense of movement fluidity and pressure control. That said, it boils down to tablet acclimatisation I reckon. :)