I've had my BrewDemon clear fermenter for about 9 months and have brewed about 20 times in it......... I fill it with StarSan right up to the rim for a day or two before, then slosh and dump just before transferring the cooled wort into it. I don't see any sign of it degrading from the StarSan, and strongly question that assertion..........
The BrewDemon is an extremely cheap thin throw away vessel.....but seems to work fine. My spigot broke as it tightened the nut when I installed it (by hand and not very tight), so I replaced it with a quality spigot for a brew bucket........ after enlarging the hole. They offered to send as new one, but I said "no thanks". I left the hole for the fermentation lock plugged ( I remove it to clean the fermenter ), and drilled a hole in the lid to get the fermentation lock higher so it wouldn't pick up krausen....... I brew 2.5 gallons and there is not enough head space for the krausen I usually see.
The conical bottom is just for looks as far as I'm concerned......
A much better fermenter is my other fermenter which is a 3 gallon acrylic ice tea dispenser from Walmart for $20. It is far sturdier, and far easier to clean. This is the one without the "ice core" in the lid. I plugged the vent hole and hot glued a bubbler right into a hole I made in the center of the lid. It has a quality spigot...... located at about the same relation to the trub line as in the BrewDemon. The beauty of the ice tea jug is the fact that it tapers from the base to the top.........giving quite a bit of surface, and the seal is the taper.... The lid drops in and makes a taper seal that is very good. The relatively large surface area is great for top cropping yeast which I do in the most primitive fashion. I boil a ladle, and plunge it into the wort still hot... allowing the wort to cool it. I then simply ladle off the krausen, capturing the best and most active yeast.
The lid on the Brew Demon is about half the diameter of the fermenter, and the internal "features" such as the threads just make it more difficult to clean.......... I like the large opening on the Walmart "fermenter"..... I also like the sturdy material. I'll be buying another of these.
H.W.