the first Sigma was smiths attempt at the polymer pistol. the early models were less than perfect. the newest models are shunned due to the Sigma's Stigma. also they are an economy pistol. perfectly functional, but for 250$ with 4 mags dont expect much. glock clone, no external safety
the new M&P is better built. external safety. better feel in my opinion. its also close to double the Sigma's price.
smith also maked a few other polymer and a large number of metal frame autos.
some of these were not so warmly welcomed, some are classics with proud historys, such as the Model 59, and thier .22 the Model 41