I've done about 40 all-grain 5 gallon batches so far. Recently, I've done a couple 10 gallon batches, and I have to say, I'm strongly considering moving to 10 gallon batches exclusively. It seems to me that for a slightly increased time investment (the additional heating/cooling adds a total of about an hour for me), I end up with twice as much beer.
Why don't more people do 10 gallon batches? Is it the issue of moving that much hot wort around? I confess I have a Chugger pump that I use for chilling, and for transferring the wort to the first carboy (I use gravity and an autosiphon to fill the second carboy). But my boil kettle (15g), mash tun (70 qt), mill (Barley Crusher w/ power drill), and all my other equipment can easily handle 10 gallon batches, so it seems like a no-brainer.
Is there an army of dedicated 10 gallon brewers out there I'm just not aware of, or is there some other reason people stick with 5 gallon batches?