I switched from a traditional scabbard to a plastic-lined one about six months ago. The difference in my boning knives is night and day. | Butchers - Opinions Matter
But I've always heard plastic liners can actually dull a blade faster, @elliot_thompson. The plastic can create a lot of friction and static, which wears down the edge. A lot of sharpeners I know say a simple cloth or felt liner is better because it lets the blade slide out smoothly without that extra drag.