When I made the switch to natural deodorants I was struggling (and stinky). That is, until I found Native! They have so many amazing scents that ACTUALLY keep you fresh all day. They also have a "sensitive" line which worked wonders for me. I've had bad reactions to some other brands and the "sensitive" line at Native cured my sensitive underarms and my stink.
Sometimes when I apply too much and then go to the gym I'll get some little white sweat drips coming down my arm. I'll go ahead and blame that on user error as that's easy to avoid by applying a little less.