Some sheaths are obviously made to meet the lowest possible price point, and usually this is pretty evident. They look terrible, they do a poor job of retaining the knife, they start to fall apart, and...all in all...they just look and feel like junk. Otherwise, it comes down to what you prefer in a sheath design, based on experience.

Personally, I'm not usually a big fan of leather. I prefer kydex, as I find it to be more durable, safer, and it doesn't hold liquids and smells like leather tends to. I also don't like sheaths that flop around while I'm walking, as I find it annoying. Finally, I don't usually like sheaths that use a tab of fabric/leather to secure the knife, as I find this rarely works well and often gets cut off accidentally over time.

If you notice, the sheath that comes with the Benchmade 201 has all of these things, which is why I can't stand it.