The dip tank method worked best for removing everything on the exterior & interior sides. For a body shell, it's pretty expensive and few guys have big tanks.
If you're only doing exterior surfaces, it's kind of a choice between the relative downsides:
Media takes a while to blow out of every nook & cranny & crevice, and someone who's not careful might warp a panel depending on what media is used. My paint rep advises against soda (negatively affects adhesion).
Chemical paint stripper is nasty, toxic, messy stuff, but the mess is easier using plastic tarps.
Mechanical (sanding) is dusty, requires a little care, and some contours (flanges, for example) are difficult to access & strip completely. It's probably the easiest & least expensive to do, though.