Joined: Aug 2010
Posts: 12,688
Likes: 2,094
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I have only used chest type ones, I was unaware of a arm band one. But chest ones are trouble free in my opinion, that is what I would suggest, have used them for years. I usually put the wrist watch receiver on my handlebar.