I purchased a 20 SF in late February and have had 4 trips to the range. Shot the first 300 rounds with the gun completely stock from the factory. Then I installed a GlockMeister non-captured stainless steel guide rod. This is the only modification I plan to do. There are 300 rounds shot with the steel guide rod. There have been zero malfunctions so far thru 600 rounds. This G20 SF is not the first 10mm pistol I have owned but it is my first Glock. I got rid of all my other 10mm pistols and I have another G20 SF on order. The G20 SF I have now functioned flawlessly with six different brands of ammo, both ball and hollow point, and I even run some of my stash of original Norma 200 and 170 grain thru it. I plan on getting more range time and when there's 5000 rounds shot thru it I'll make another report for you 10 lovers!