I use 6.5 gallon glass carboys, the "brew haulers" are life savers. I don't understand how anyone could not use them with 6.5 gallon carboys. Never have had an issue. Ever.
Glass is easy to clean, easy to sanitize, doesn't scratch, you can see your beer as it ferments...I also use the shake method to aerate, which isn't possible or very easy with buckets. Plus I can have a better blow off tube attached, if needed. Yeah, it's a little heavier, but it ain't that heavy.
Wins all around.