The H290 is a pretty good part. I'm not sure how much attention was paid during its design, if it was on purpose or accident, but whatever the case it does a surprisingly good job in terms of directionality and smoothness of response. It's perfect for this application. From what I've seen, it's better than most of the so called waveguides out there.

The wood horn is only slightly better acoustically, mostly in the vertical. Its larger size helps a great deal reducing mouth reflection when used as a stand-alone horn, not mounted on a baffle. That's its intended use, so it was important to make sure it worked well when sitting on top of a cabinet instead of mounted flush on a baffle. It was designed to be a beautiful piece of art that also worked well acoustically. We make it from wood with interesting grains and cut graceful lines on a CNC machine. It really is a work of art as much as anything else.

You lose the aesthetic appeal when doing an injection mold. I suppose it could work if the whole cabinet was painted. A highly polished paint job, something like a piano finish, perhaps. That could be a good look. But the whole point is that for baffle mounting - where I see an injection molded horn being used - the baffle helps horn loading and it doesn't need the larger mouth for this frequency range. The H290 is a fine horn for baffle mounting.