| About the stripping... I would say it depends on:
1) The finish and the body
2) Your definition of a power sander
3) What finish you want to use
Chenical strippers can cut down stripping time, but they can also make a sticky mess... and they usually have to be used outside because of the fumes. (Opening a window isn't a "well ventilated area.") Also, the wrong chemicals can have an adverse affect on plywood.
Some people use heat-guns or hair-dryers, and they say that certain finishes can be scraped off with a spatula... but I've never tried it.
Sanding works, if you're patient and careful. Using a 5 amp belt sander can turn your guitar body into an ugly looking bas-relief carving faster than you can say "OH S**T!" Using a cute little palm sander can take as long as building the pyramids.
If you're going to go with a "natural" wood finish, then you're probably don't want to sand down your old body. You'll get better results (and have less frustration) if you build/buy a new body.
If you're just putting on new paint, you may be able to sand out the imperfections in the old paint, and shoot something over top of what's left.
It all depends on what you have and what you want. | 
