I just use my sewing machine to wind bobbins. It's fast, smooth, and easy. I can't imagine paying for another gadget.
Even if I don't want to unthread the machine (although it only takes a second!), I can wind bobbins by placing the spool on the other peg or on a cone thread adapter or even holding it loosely in my hand.
The best thing to do, of course, is wind enough bobbins for your project ahead of time, but winding bobbins is really easy on the sewing machine!