I see POTV sells a silicon WPA for $25 and a glass one $10 cheaper. I would have thought it would be the other way around?
Any opinion as to which one is better?
The silicone wpa is designed to "break away" from Mighty (if under stress) without doing any damage to
Mighty's shell. You can also get them from Delta3dStudio, where they are made, maybe pick up other accessories that he makes.
I used one for years, no problems.
The glass verion is also nice, diect to glass is often preferred to any silicone in the path...
There are cautions with this type about over tightening, with risk of damage to Mighty, but I think that issue is not happening very often, if at all, in recent years.
With the glass one you have to relocate the screen, it is too far from top of the bowl. I use no screen in this wpa, but I place a flat 5/8" pipe screen atop the chamber load. I've also used one of that screen, domed convex side out, in the wpa.
My suggestion is to go with the silicone, unless you have some specific issue with silicone.