I like the demijohn, Steve but there are some cautions that go along with it. I definitely needed to construct a dolly for it. That makes moving it around the cellar much easier. They are only useful if you are making larger batches of wine, i.e. if you are only making 6 gallon batches, they are not the answer. They have thinner glass than carboys and require more careful handling. There would be a concern in pumping into a demijohn due to the thinness of the glass and the pressure involved (which is another reason I am looking for a transfer pump). Once you choose to fill it and it is on the floor, you are fairly we stuck with that.
On the positive side, they make bulk aging a large batch more consistent and easier to treat/adjust if necessary. They have built in UV light protection with their plastic enclosure. They hold roughly the equivalent of three 5 gallon carboys and are a less expensive alternative to three carboys. I recommend looking at L'Uva Bella in Lowellville, Ohio. Their demijohn is $59, recently up from $49, but still a good buy. Three new 5 gallon carboys would set you back at least $75.
