I have to have the plastic. I'm too clumsy to use glass. I dropped my PET carboy full of wort in my lager chamber yesterday. It fell a foot and bounced. I hate to think what would have happened if it were glass. Also 5+ gallons of wort weighs around 50 lbs. Add the weight of the glass and it gets very heavy to move around. That is why I prefer the Better Bottles.
"Doubt is not a pleasant mental state, but certainty is a ridiculous one." - Voltaire