I've been fermenting in one 6.5g carboy, 1 6g carboy, and two 5g's for secondaries.
This is an exciting week though, I picked up a couple of 6g better bottles from the recent BOGO offer Northern Brewer Had. I'm interested to finally arrive at my own conclusions on these. One thing I can say for certain, the two boxes arrived and for their size might as well have been empty. They barely weighed as much as the cardboard they shipped in. I swear the 6G better bottle weighs less than the handle I have on my glass 6G.
I love my glass carboys, I love knowing they are spotless but depending on how things go with my post-primary cleaning, I might have to switch to these BB's. If I don't like them, love them really, I'm going to unload them to some lucky local brewer at a great price!
First observation: I usually sanitize my carboy, then flip it upside down in a 2 Gallon stainless spaghetti pot on the floor to dry. I've currently got the better bottle sanitized and flipped upside down in a....Oxo 2-cup measuring cup..ON the counter.