The Opinel I have used most is the #8 Carbon Pocket Knife, and it is this series I am speaking of -- I like them quite a lot, and I like how they can bridge the gap between a pocket knife and a utility knife - cheap, aggressive slicers, crazy easy to sharpen: you can use these for tasks that you would not want to expose a nice pocket knife to, and if you damage the Opinel blade severely during use, it's very easy to revive (and cheap to replace.) As the steel is pretty soft, they rapidly dull, but this is largely by design since someone woodworking has to sharpen their knives frequently, regardless of the steel. With an Opinel, that process of sharpening is easy, fast, and can use just about any sharpening product. Heck, as they begin to dull, you can strop them on either a belt or a pair of jeans and rapidly revive the edge to a point of being screaming sharp. Additionally, I find the blade works well with a toothy edge, and should one want the toothy edge it's as simple as using a medium-fine stone.
I also like how you can take mustard (or vinegar or grapefruit juice), rub it into the blade, then cover the blade with bubble wrap and leave it for a few hours and wind up with a mustard patina that not only provides rust protection, but leaves a really cool pattern from the bubble wrap.