Well, it could just be my imagination, since I know it has the new part and I want there to be a difference, but it does seem to cycle more smoothly. I got it with the OEM recoil spring weight of 17 lbs. Of course, it looks better too...but that really is subjective.

I should take the OEM polymer guide rod to the range with me, and fire some rounds alternating between the two, to do a comparison of how it feels. Even if there is no appreciable difference, I'd still go with the steel guide rod...I've replaced the polymer guide rod on any pistol I've owned that had one, if there was a steel replacement available.