[burntwater]

I haven't done it myself, but everything I've seen says the AT is a completely different kind of experience. You need to (should be) in reasonably good shape, you have to carry a lot more gear (ties into the first point), there's a lot more planning and logistics to work out, and it's a much more rustic experience (literally camping every night, with a few hotel stays).

For the Camino, I started out 40 pounds overweight, I did zero physical training in preparation, I had to plan basically nothing except my flight, arrival day and departure day. I was able to do it with literally only a few weeks notice (I had never heard of it until a month prior.)

Ultimately what I'm saying is the Camino trails are much more accessible to a wide range of people, as long as they're able to fly to Europe.

ETA: I should perhaps explain that the Camino trails, or at least the most popular trail I took (the Francis) is really more of a walking trail than a hiking trail. It's mostly flat(ish) and is much closer to what's depicted in pictures posted on The Great American Rail-Trail.