There are so many Mora knives that I am lost (that's not too dificult). If you have to buy just one to carry in the field with you for hunting and survival in case you get lost, which model you would pick?
Just look at the Moras the experts carry. Cody Lundin (98.6) carries one of the red handled Moras.
I have at home and have tried the Frost S-1 and 164, the KJ Eriksson 510, 545 and 911. I have split wood with battening, made fire boards, and carved fine tinder that will start with a ferro rod. They all work very well. I must say that the handle on the S-1 is the most comfortable when you are applying a lot of pressure. There are no bumps to create pressure points while you are working. Also the S-1 with the laminated blade seems to get sharper. The back of the blade is much smoother than the other Moras. This makes it more comfortable to use. I did feel it was necessary to grind down a small part the the edge where it is close to the handle. This also created the perfect place to scrape a ferro rod.
Let me describe a new technique I have been using with the ferro rod and a scrapper. You can hold the scrapper and pull the ferro rod away or you can hold the rod and push down the scrapper. Most experts hold the ferro rod and push down the scrapper. It does work better but I keep scrapping my knuckles on the hand with the scrapper.
Here is what I do now: put your foot close to the tinder. Rest your hand holding the scrapper against your shoe/foot. Now pull the ferro rod away. Because the scrapper is very stable you get a lot more sparks than if you are free holding the scrapper. Because you have the scrapper at the right spot, your shower of sparks goes where it will do the most good.
Give it a try and tell us what you think.
Having said nice things about the Mora I have to add that I only carry one for fine work. I carry a Cold Steel SRK for prying fat wood from stumps and other heavy tasks. My Camelbak always has: a Mora, an SRK and a Gerber Sportsman's saw. I also keep a Leatherman Charge Ti clipped in my pocket.