They are very reliable if you stick with ammo they like and hold them very solid.
I've never had a failure-to-fire with 115gr FMJ Winchester and PMC, nor with 115gr JHP Speer GD. Mine hates Hornady Critical Defense though.
It's only experienced three failure-to-feeds. It was with three different people (myself included). Each time was due to limp-wristing on our initial experience firing it. With so little weight and such a strong recoil spring, it really needs your grip for the cycle to work.