well the ducky zeros are just a cheaper shine at $115 ish fullsize but your looking at smaller then theres the vortex race ($118) and Poker ($110). i never tried them but if i were to drop money at this sec id be getting one of those.
thers also the vortex PURE for $105.
but those are all super smalls. the one that is comparable to the cm rapid could be the ducky pro at around $99