Herrett's will make their grips to fit a tracing of your hand, and they handle recoil very well. I've never tried Nill grips, but I would think that the all-important individual hand differences would be a determining factor as to which is best. I have read many happy reports of Nill quality and feel.

I find Herrett's much better than Ahrends, for me. Also, the older I get, the lower velocity loads I shoot

It's rare for me to shoot a .44 at much over 1100 fps anymore, and most are below 1000.