I've had no trouble with edge retention, but I do tend to sharpen my knives frequently to keep them very sharp. My Opinel knives are great for food prep - they will slice a tomato like you wouldn't believe and I've used my #6 as a steak knife, it slices the steak so very easily. If you want to take a camping food prep knife that you can fold up and put in a pocket with not much weight but great slicing capability - the Opinel is a good choice.
Opinel knives are made very cheaply and they are cheap to buy, but they aren't junk. They are just a cheap and simple knives that actually work very well. Not everything that is cheap is poorly made crap that will fall apart within a day, some cheap things are just very basic but work very well.