There are about a dozen Opinels on my knife shelf. I have been using them for about 45 years, mostly in my motorcycle touring kits. They are a simple, elegant design, friction folders with a classically simple locking ring to keep them open, and on the more recent models, closed as well.
I had always considered them to be toolbox or glovebox knives, because the flared pommel made them a bit awkward in the pocket. The no. 7 and No. 8 were the sizes I used most. Once I found out how easy thy are to modify, I started carrying one regularly. Mostly I carry the 6, but the 8 with flattened sides and a trimmed pommel also rides nicely in the pocket. The also have a garden knife with a slimmer handle. If you look online, You can find a wide variety of modified Opinels, many of which are works of art.
If used as intended, as a cutting tool, Opinels are hard to beat, especially as slicers. When you consider the price, in the range of $10-20 for the basic beechwood-handled models, they can't be beat.