I use a thumb wheel at work wearing gloves. I'd prefer to use a foot pedal, but I don't have the luxury of sitting, or even being in a predictable position.
Having said that, I would prefer a foot pedal.
Also, a momentary switch is nice, it's almost impossible to crank the thumb wheel down quickly when finishing a pass. So you end up with goofy arc control, and more heat than you need. You can help by having your machine setup as high as it goes, so you don't have to turn up the thumb wheel as much.