My first was an RC4 but for whatever reason the cutout for the finger groove is too snug on my index finger.
I could get along nicely with only an RC-3. It's one of the best all-around knives I have ever used, works on everything from drywall to paint scraping to cardboard, rope, meat and wire.
For anyone in that thread about Tactical Izulas talking about penetration of meat - the knife goes right thru the top of a naptha can. Meat's not going to slow it down.
It's a great size for unobtrusive carry under any circumstances, out of the way until you need it. Rather handy as an urban problem solver as well as a woods-knife.
My preferred configuration is with a round pommel, no serrations, whatever the grey-ish handle slabs with the green liners are (though tan canvas micarta or G10 would work just as well)
I have never used the nylon backplate and likely never will. Mine is carried IWB with the clip thing around my belt. I may have another sheath made for it, but really have not seen the need yet (though want is a strong motivator)