I checked out the 21SF at a local shop a couple of weeks a go and found that although the grip was not as small as I originally had expected, the reduction was enough for me to buy one. I currently carry a 21 and the grip is acceptable bu at the outer edge of what fits my hands. The slightly smally SF grip fits me better. That said, I have only seend SFs with Picatinny rails here in Centeral Indiana. I have not seen any with the Glock rail. Does anyone know if Glock rail versions are available in the U.S. yet and if not, when they will be available. Thanks.