I'll take whatever I can get. I have a hodge podge of carboys ranging from 5 to 6.5 gallons. The 6.5 are old kind that they used to use for transporting sulfuric acid. The 5-6 gallon ones are your standard run of the mill carboys.
Plastic, Glass and, Stainless steel all have their merits. iThe reality of it is, in the end what really matters is what works best for you within your budget in your brewery.