Straight-Aim Engineering has come up with a significant discovery in putter insert design that actually improves putting accuracy in a measurable way. It provides die-at-the-hole distance control utilizing the principal of ( EVR ) Error Variance Reduction. EVR displaces impact force vectors from 180 degree (rebound) to lateral (90 degree) vectors in relation to impact force. 

The EVR insert has been tested objectively, using a putting machine, and has reduced putting error (keeps putts closer to the hole) by as much as 25% as compared to putts with a standard metal or polymer striking face.

Conventional wisdom is that putting is all about "Feel" and I believe this is true. However, the bottom line is about "Results" on the course. In other words, if your putter feels good but your not getting the results, it's time for a change. Initially that change to a better putter might not feel quite the same, but you eventually you get used to it and it all starts feeling good again. 

We thoroughly tested and played the Black Mallet with the standard polymer insert, their best seller. Not only is it a well engineered putter with a over-all good feel, but it also has a ball pick up feature built into the bottom face. The best part about this putter was the fact that it feels pretty good to begin with. There was not a long period of having to get used to it. This is a putter you can just pick it up, practice with it a little, and you're good to go. 

You can get more info at  www.straightaimgolf.com