The choice depends on what you are trying to accomplish (muzzle flip or frame battering), the caliber of the gun, whether or not the gun is compensated, and the barrel length. The Harrts works best on larger caliber, longer barrelled guns (like a govt 1911 or G21), and doesn't work at all on compensated pistols, which is why all the IPSC race guns use Sprinco units. For a 9mm (like a SIG P225) or a short barrelled big caliber gun (like the G30) then Sprinco is a better choice. One BIG advantage to Sprinco is that when you order one you can try it for 30 days and if you don't like it send it back for a full refund. I usually try the Sprinco first and if it doesn't do what I want it to I get my money back.
