It is so easy to have thin walled tubes retrofitted, forcing cones recut, and back-boring done, I've just got to ask why bother with a Polychoke? They are the absolute scourge of firearms accessories, right next to stock compasses and see-through rings.
The only thing I can think of is that people have sentimental attachments to them - a lot of folks grew up shooting a shotgun with a polychoke on it. Thankfully my old man never saddled me with one, mainly because he thought they were pretty awful as well.
And every time I see see-through rings, I think "oh look, a died in wool redneck".
Gigantic carvings of animals and crap on the stock is right up there as well.
Brian.