The duplicate blades never caught my fancy, but I fell pretty hard for the RR Improved Muskrat, with one slender California clip, and a long, slim sheepsfoot/wharncliffe blade, in smooth tobacco bone. It was my most frequent carry for a couple of years. The straight edge was my primary blade. I gave a couple as gifts, and bought a spare in case they ever stopped making them.
The spare turned out to be a pretty good idea, because I don’t think RR has made an improved muskrat for a few years now. Case called its version of the pattern the Hawbaker. I have never seen one live. I guess they are pretty thin on the ground now, too, and pretty spendy. Until I come across one at a price I like, I will be okay with my $8.00 version.