The big difference between the RaceFace Half Nelson grips and most other single-clamp models is a plastic sleeve that runs the full-length from the inboard clamp. The purpose of this is to stop the outboard end from twisting, as it can do on simpler grips, and it works well.
There’s obviously no hard outer end-clamp to bruise your palm on, and the Half Nelsons also save 15g a pair compared to a set of full end-capped lock-on grips.
Far-side finger ridges and the ‘Garbanzo contour’ pattern add extra wet/slimy conditions grip to an already tacky, slim profile. The feel is definitely firm rather than ‘padded’.