Working in the sun doing heavy lifting in past summers, I have found that many deoderants don't rise to the challenge for me. Even if they manage to keep me from being stinky, I'm not dry. But I bought mitchum, because I heard that it used to be sold completely by prescription for excessively sweaty people. I have to say that this is the most effective deoderant I've ever had. I even tried skipping a day once, and it completely worked. I am not half as self-conscious as I used to be when I wear mitchum, and I've been using this brand almost exclusively for about 3 years now.
The only downside is that they don't have a wide variety of smells so generally you smell like powder. And whatever is in the stuff, don't get it in your eyes or on your tongue--not that you'd have that problem, right? Seriously, don't do it.