We use them every day and they are the most clear and easiest to use communication systems we have tried so far. They are fine in the rain and saw dust and can handle the rigors of tree work, but, mishandled, they can be easily broken. The boom mics are fantastic for being able to talk over chainsaws or other equipment but are not IMHO strong enough for daily tree work, so we save them for special occasions. The shorty mics are great for daily use and much more convenient. Getting the headsets to fit comfortably with a helmet does take some trial and error before getting things just right.
I broke my boom mic in about four weeks of use and than snapped the plastic frame in between the ear sets by an over exuberant stretch getting it over my hard hat. I'm more careful now. The Sena company is trying to establish themselves as responsive and customer friendly and replaced both broken parts under warranty.
All and all we realy like them.
Dave