Out lasts everything.
I love this cog and I have tried everything out. Some have work well for a while and some will bend or snap after a week. This Surly Single Cog is how all bike components should be made, to with stand the test of time. They have a wider base that keeps your freehub body in perfect shape. You can also find a perfect chain line with out moving to much. Just flip it over for 4mm inside or outside, spacer kits sometime don't have one small enough for that fine tune adjustment. These cogs have a tall tooth profile that is essential for preventing chain skip from the extra torque from a single speed drivetrain. Another thing I love about the cog base width is 4.35mm, so I stack a 4 of them up and use a 9-speed shifter for a slop style/ free ride set up. And I have never had my chain fall off and I mean never. Spend a little more now and save a ton in the long ride.