I'll go multi blade every chance I get.
I like having two or even three blades on hand just in case of a real dirty deed cutting job. I don't know how many times I've looked at something, and thought "This is going to screw up my edge for sure." But then I just go ahead and use the 'minor' blade of my knife and go on with the rest of my day knowing my main blade is still fine. Plus with two edges, you can have two very different style of edges. One at a steep angle for those dirty deeds, and another with a slighter angle for fine slicing.
There's an added feature that has nothing to do with cutting, but I didn't find out about it until I became a senior citizen. A three blade stockman ot two blade jack will have a wider boxier handle. When you get to old fart status, you may find that with arthritis a fatter handle is nicer for older hands to grip with. Better control and able to put more force in the cut if need be. Just like a Victorinox recruit will be better to grip than a Victorinox bantam, even though they are both 84mm knives. Or like a peanut is easier for me to grasp than a Case pen or mini copperhead, even though the one gives another 1/4 or 3/8th of an inch in length, they are just to slim.
For older hands, fatter is better, and if we get an extra blade in the deal, then that's just gravy on the taters.
Carl.