I put on a set of PT Nitesites, but really, the best option comes right with the 99, and thats the size change grip inserts.
Let me explain, the Christmas before last, I cut my hand open on some window glass, while helping a resident that had locked themselves outside in the middle of a snow storm. The wound was pretty bad and cut the nerve that supplied feeling to my little finger on my right hand.
The doctor that stiched up the hand said that nerve tissue grows back so slowly, that it could well be a year or more before I regained any feeling in the finger, that is, if I regained feeling in it at all.
Now I do not know how many of you have ever tried to attain a good shooting grip with a dead pinky on you dominant shooting hand, but let me tell you, it's more of a problem than you would think.
My large frame Glock 21 became all but useless
But...Enter stage left, the Smith & Walther 99/40, I had just bought a couple of months back...A quick change of the grip insert, to the smallest size and the ergonomics changed to a much more comfortable and secure grip, that helped with the loss of pinky finger control due to my injury.
In other words the adjustable grip inserts, turned out to be not just a gimmick, but a true stroke of genius on Walther's part, worth every penny.
The good news, is after two years, the feeling is beginning to come back to my shooting hand pinky, But that does not mean that I will be going back to my Glocks or 1911's, No, I've become so used to and in love with the Smith & Walther, That I really have no desire to carry anything else in my daily wanderings.