Yes it is much faster, and that's a big help when preparing food. But it's not my main motivation with onions. Albi, what do you do? Wear goggles when chopping onions? Whenever I chop onions the old fashioned way, I'm crying crocodile tears. But worst than that is the stinging and burning in my eyes for a long while afterwards. Shallots aren't so bad -- and anyway, shallots need to be chopped way more than regular onions, so there, I gotta do it manually.
OTHO...all other chopping I do by hand. I really love doing it by hand and usually the scents that are released are wonderful, especially with herbs like dill or basil.
BTW...the guy selling slap chops wasn't there last night. Drat. I figured a street vendor is probably selling for about $10. Well, that's what I'll pay. At that price it's worth it to see if they break immediately or last a while. Besides, [blush] I actually like the commercial!