TFL member Lendringser did a review recently on his M2.
The main differences are a rotary barrel, and the cost is kept down by less fine finishing/polishing & detail work relative to other SIG-built pistols.
I've fired his; we ran a fast few boxes through it at 7-10 yards. Three mags would make one ragged hole with ease in rapid fire. We were firing both Atlanta Arms FMJ and Remington Golden Saber Bonded JHPs; both ran fine.
