I've been reloading without a device like this for MANY years ... but .. I've started shooting in competitions and wanted greater consistency in my competition loads. You can more easily build "test" load groups to see what works best for each of your guns. It never varies more than .1 grains and usually below your desired load. It also gives you a count at each load you select. The owner's manual is accurate in that it warns you that cleaning it after each use will seem cumbersome, but after 4 or 5 uses it's no big deal.
I have had displays not explained in the manual but I understood what "ERR" meant ..... too much powder was dispensed ..... do not use!!!
Pros: Greater consistency and accuracy
Cons: A challenge to clean .... at first
This review was written in the old system and had content requirements that are different than reviews written today.