I bought this block 2 months ago. The block consists of a column of tightly packed thin plastic rods. When you slide in a knife, they get displaced and snugly hold on to the knife. There are no slots like traditional knife blocks, which allows you to slide in many many more knives, and in any arrangement you choose. I currently have 13 items in the block, including a big Chinese cleaver, honing steel, 5 large knives (ie, chef's) and 6 small knives (ie, pairing)...and there is still room for more! I was skeptical at first, but now I am a believer.
The plastic rods are approximately 8" long, so longer knives will stick out a little. But they still get held in place by the rods.
Pros: Fits more knives than a all-wood block. You choose the knife configuration. Cheaper than most all-wood blocks. Washable. Plastic should not dull knives.
Cons: Angle is a little too upright, so I need to slide the block out from under my cabinet (or tilt it) to get at some of the knives in the back.