It is true that the 18 is thicker than the 14 because of the wider design of the brass guard: This is why a sheath for an 18 will have a much longer snap loop than a sheath for a 14, and so, unlike what is claimed everywhere, the sheaths are definitely not interchangeable... The brass pommel is also designed broad, for the same reason as the guard: To contain the possible paracord wrapping. In my opinion, on knurled model 18s, a narrower guard and pommel should exist as an option, but I still like the 18 the way it is...
Wrapping with paracord does make a handle for big hands, but knurling makes this optional.
When used for chopping, the confort of the 18's handle is probably on par of more with the thinner Model 14 handle. I would not be surprised if in the long run it was much more confortable for chopping than a 14, especially with paracord in place...
I have yet to test this, but I am sure the sawbacks on many Model 18s (the saws differ greatly from knife to knife) are actually quite a bit more useful on wood than is generally assumed: They are cut very sharply edged and are thus very aggressive. Also, because they have a much smaller cross-section than the full-width saw teeths usually found on other similar knives, their initial cut into wood is much easier and faster: The sawing stops at only about half an inch into the wood, but on a 2" or less diameter piece of wood, it is enough to give a weak point to more easily break the wood... The saw is sharp enough it could even finish the break by cutting the last remaining "strip" that always hangs on, without resorting to a risky chopping motion near your foot...
The argument that the Model 18 is heavy has of course been proven wrong above... It is in fact much too light because the blade is not a true 1/4" thick, but more like a 3/16" stock, and barely even that near the tip... The Model 14 I have, with the same Model 18 blade, is for its part starting out a bit thicker than my 18 near the guard, but has essentially the same problem... This means chopping power is likely low on either, although the very thin hollow grind edges do help deeper bites... This limited chopping power is a problem on 18 style blades because, saw teeth or not, they have a big continuous top grind that makes batoning less effective. The sawteeth do worsen this issue... On that point the standard clipped Bowie blade Model 14 does have an advantage, in addition to the thinner guard for carry... The clip does reduce the Bowie's batoning ability as well, but some flat surface is at least present.
A small flat area in front of the saw, even if only 1/2" long, would have helped the Model 18 design, but it was designed long before batoning ever became a common practice... The thinner 3/16" blade stock also reflects a time were even fairly large, but not huge, knives were stickers and/or slicers, but not wood choppers... The advantage they derive from that is that they still have among the thinnest big knife edges out there...
Gaston