Although I think the Opinel is a great knife for the price, I have two gripes concerning use in a survival kit.
1) I've found, as Chris K. indicates, that the knife can very easily bind in a closed position. In my case, the wood was too vulnerable to moisture and swelled around the tang and hinge of the knife.
2) There are plenty of knives which give you the same blade size, but with grips which are more flat and therefore more easily packed.