I am not a Glock or polymer pistol fan by any strech but I have shot both.To me the Sigma has a more comfortable grip and trigger,The magazines are metal,it is made in the USA,and it is priced@ around 1/2 that of Glock with free magazine rebates also.The M+P is a vast improvement over the Sigma in the respect that you have multiple grip configurations,and you have removed the reason why Glock probably holds the title for the most accidental discharges world wide which is that you have to dry fire it to break it down.Because of the breakdown method for the Sigma and Glock I advise my students against getting either as a first semi-auto until the new shooter gains more experience .If the shooter still wants a polymer gun I advise they consider the M+P because you don't touch the trigger to break it down and ,God Forbid,if there is a round inadvertently left in chamber the magazine release safety is there also to guard against a Accidental Discharge.........Mike