Me too. It's not just a shape difference,but a material difference as well,so far as that goes. I think if it's clean,sanitary,& well sealed it shouldn't make a difference. They say plastic can leach o2 into the beer,but I tend to think that'd only be true for PET bottles. They're thinner than a ale pale,& clear brown. I don't think they're taking into account the fact that every ferment is different.
Seems to me that'd apply here as well,even though the constituents are the same. The only real change in shape would be the bottom. The bottom edges on a carboy are rounded,whereas the pale would be close to a right angle.
Everything works if ya let it-Roady(meatloaf)