The TASER is a tried and true weapon, with a significant market share and user base. The Stinger is the new kid on the block, and it remains to be seen if departments will go for the new thing, or stick with the older, established thing. What is safe to say, however, is that the different design features of the Stinger will give rise to consideration of the TASER's features. Whether the Stinger succeeds or fails, perhaps this will lead to modifications that will enhance officer safety, and that, too, is a good thing.
These companies have provided products geared to making police work a safer profession. As long as they challenge each other in the marketplace, and we "in the market" use common sense (along with that "BS Detector"), law enforcement can only benefit. The goal for all of us is to keep officers safe, and to safely and effectively serve our communities.
Stay safe, and wear your vest!