Definitely get one where the control/readout unit can be kept on the shooting bench. It is easier to read and safe from stray bullets
http://forums.accuratereloading.com/...43&m=446105658
If you get a Chrony, the Master Chronys have the sensor unit separated from the control unit by a telephone-like cable (but a telephone cable won't work) and my sensor unit wears armor.
Good luck
Lost Sheep