First I like how these are made out of a rubber-like material rather than plastic. I used the plastic ones for a while and found them to be a bit slippery. These give me a nice grip.
Second I like the "valley" down the middle of the rail cover longitudinally. Click on a close-up view of the picture and you can see what I mean. It's not just a ladder "rung" that completely evens out the gaps in the picatinny rail; this valley down the middle of the rail cover gives texture to the rail once installed. It may actually be the peaks on each side of the valley which protrude above the picatinny rail that gives it texture.
I tried a set of these and ended up changing out all of my rail covers!
Pros: not slippery, easy to work with
This review was written in the old system and had content requirements that are different than reviews written today.