Think it will depend on how many layers of paint there are. Mine only had one layer so came off easy. Over the past couple weeks, I've been stripping my car. I've been using 80 grit paper on a dual action air sander. Just buy a big roll and change paper often. You could also get some 50 grit to cut through the paint and primer quicker, then switch out to 80 when closer to the metal. I was surprised, it didn't take nearly as long as I thought it would to get to bare metal. For the tighter spots and places I don't want to use the sander, I've been using a 3M Scotch-Brite clean and strip roloc pads. I usually use the purple ones, but also have some of the black ones as they were out of the purple ones. I found the purple ones lasted longer. These things last quite a while and go a long ways for stripping.
http://solutions.3m.com/wps/portal/3...beRJ5GMFSMV0gl
The other thing I'm using is a Nyalox wire brush. Both the 3M and the Nyalox fit onto my air die grinders so are easy to use.
http://www.summitracing.com/search/b.../?autoview=SKU
This one's warn down some already
There are several ways to strip the car. I found this has worked well for me doing it in my garage at home.