I was in the same predicament that you're in MOF. I ended up with the Necker because the sheath carry options were better. It's a great knife, great sheath (mine has zero rattle, and I have noticed the retention spacer things do wear the edge of the knife, but only if it's somewhat dull). My only complaint was the edge on mine wasnt ground very high and right now I'm having a hard time keeping it sharp. Once I re profile it it should be good. I also got the KA BAR TDI Clip which you can screw on the sheath and carry the knife IWB. Its awesome, sticks right to the hip and doesnt protrude through clothes.
I'll be getting an Izula shortly, I think (because I'm a little happier with my RC4 than I am with either of my Beckers) that I will like the Izula more, but I do wish the sheath was easier to carry IWB. Plus, you know about RAT's stellar warranty.
Tough call. Just get both.