not exactly a grip shift fan - but have a few bikes with grip shift shifters and they shift well …
SRT 400, 500, 600 7 speed with Shimano rear derailleurs on a few bikes (including two in background of bottom pic) and the 8 speed bike (Litespeed) below with SRAM shifters and rear derailleur (ESP 9.0 SL rear derailleur ?) …