Much more important than what type or brand of knife, is that it is sharp.
That said, I started with one (Leatherman CS4) and it did everything I expected it to. It is my normal backpacking knife and I have carried it on hikes for years. So no surprises there.
The next thing to consider is durability. I saw a couple cheap "Swiss Army" knives fail. Also, many others that were almost as dull as the knives in the communal kitchens. Not much point if that is what you have.
One last thing- Is it going to add value? If you don't plan to cook you don't need much of a blade. If you don't drink wine you won't use a corkscrew. If you don't wear glasses there isn't any use in a tiny screwdriver. Personally, for me, the weight vs the uses made it worth taking. Others would be better served with a small, simple blade.
Something to consider beyond pocket knives. Are you planning to cook regularly? If so consider a kitchen knife. While my pocket knife was sharp enough to chop onions & garlic, and slice cheese, apples, chorizo, & bread it wasn't the best tool for the job. While I had not intended to cook when I started the Camino, as the days and weeks went on I found myself doing it with some regularity. So one day I stopped into a ferretería and bought a light kitchen knife with a plastic cover. Nothing like sharp, properly sized knife to make cooking more pleasurable.
