Doc, If you're talking about the soft plactic buffers like the Wilson Shok-Buffs then I wouldn't bother. They limit the slide's rearward travel and often cause failure-to-eject problems. The Shok-Buffs protect exactly one part from battering; the spring guide. It is an inexpensive part to start out with and can easily be dressed with a file when it gets battered (thousands of rounds). The Shok-Buffs do cusion a slight bit but not enough to really matter.
There are other systems that do work well. They require replacement of the spring guide and installation of an inner buffer spring. Ruger uses a system like this in their new P-345 and it really works. The down side is it takes some muscle to pull the slide all the way back. Here's a photo of Ruger's recoil buffer:
The bottom flat coil spring is the buffer. The top section shows the recoil spring on top of the buffer spring.
