A plain edge, especially in VG-10, that takes a toothy edge will cut through most kinds of rope. A sheepsfoot (rescue/atlantic salt), wharncliff (centofante 4) and a hawkbill (merlin/harpy/tasman salt) are far more effective rope cutters than say a military or a delica, but trust me, I've used an endura, a military, a large dyad, and a delica, and all of those plain edge blades worked just fine.
when you'll notice a difference is how you are cutting the rope. Are you bending the rope over the cutting edge and using the blade in the bight? then the straight cutting edge of a sheepsfoot, or the inwards curve of a hawkbill is going to surpass a bellied cutting edge. I've found that cutting rope in that fashion causes the rope to slip off of the front of the blade as you make the cut.
but, try laying the rope on a workbench or cutting table and using a hawkbill. Difficult to do. A bellied blade like the endura or military is going to be better for that job.
Serrations are good when the rope is under strain, toothy ones, that is. Try cutting a slack rope with deep, pointed serrations though, especially modern synthetics, and you will get a ragged cut, with the strands pulled out from catching on the teeth. Shallower, less pointed serrations make as neat a cut in rope as a plain edge does, i.e. serrations on the golden colorado (s30v) spyders.
I personally think that a knife without a choil (ex. the endura) or a shallow choil (ex. the military) is much better for the rope cutting that I do than the deep choil on the atlantic salt. I can't count the amount of times that the rope caught the textured choil of my atlantic salt and almost pulled the knife out of my hand.
A delica or salt 1 will be a much better cutter than the native though, because the thick native blade I found jammed up in larger diameter ropes. the blade length does matter but don't let that be a deciding factor. many sailor pocket knives from the days of sail didn't have much longer blades, and hawser and other lines on those old boats were thick diameters.
The rope composition is also a factor in the functionality of the knife. I've never cut a natural material larger than 1/2 inch. I've cut synthetics up to 1 1/2 inch with an endura, and they are no match for most of spyderco's steels. I've found VG-10 dulls after one cut on commercial fishing lines like polysteel brand floating line and neutral buoyancy (whale safe) line. This stuff will scratch the blade, and my atlantic salt is polished to a mirror shine near it's cutting edge from sawing through so much of the stuff. Polypropylene floating line is hard on most blade steels, as is polyester/polypropylene sinking line. It is when cutting those that a serrated knife will serve you better than a plain edge.
Now, after that long winded response, I can think of a lot worse knives you can pick to cut rope beside a delica.
what do you do that gets you cutting rope?
pete