I've worked in a auto-shop...here's my input.
Craftsman feel more flexible.....wrenches will open up when over-torqueing causing nuts/bolt heads to round. Tool fails, you take it into sears and get it replaced.
Snap-on feel more rigid....have broken a few getting stubborn suspension bolts off, but don't flex. Tool fails we called Snapon's #800 and a replacement tool was delivered within a day or so. Often they tossed in a extra basic tool to try as well.
Snapon also makes a much more varied line of tools..... you can find about 20 different variations of a 1/2" open end wrench (length, thickness, and lots of other wrench combos).
I will say the Snap On finish is more suspectible and shows dammage to finish....but hey, that's cosmetic. Snapon tools clean up easier because of the smoother finish also....
What do I own at home? Mostly Crafsman because of cost.....
My $.02
Edit: From comment made above:
" I saw an episode of Orange County Chopper and they made snap-on themed bike.
So I take it snap-on is the better of the two. "
No, snapon makes expensive bikes and has expensive promotional campaings.....which is part of the tool price you might pay.