I'm looking at getting a kegerator since bottling kinda sucks. I'm on Amazon and they have a fridge that can take:"1/2 barrels / Full Size Kegs (15.5gal), 1/4 barrels / Ponies (7.75gal)". I've only heard of corny kegs being used with homebrew. What's the difference between a corny and a pony keg?
I always thought standard quarter barrels were ponies. And according to Micromatic a Pony Keg IS a standard quarter barrel. The tall quarters are called "slim quarters".
Here is a link: Micromatic Chart
Ponies, generally, are just tall, skinny quarter-barrels. They look like corny kegs, but have Sankey, or other commercial beer fittings. Sometimes the standard squat quarter barrel is also referred to as a "pony" keg. I think that designation is largely regional.
Cornelius kegs come from the commercial soft drink industry and are usually 5 gallons, although there are 2.5 gallon, 3 gallon and I have seen a 7 gallon Corny keg. Anything but the five is rare and I would have called the 7 a rumor if I hadn't seen one once. But only once.
I've never used sanke (the family of kegs pony's fall into) or corny kegs, so those of you who have correct me if I'm wrong, but I believe the reason that home brewers use corny's is because they are a lot easier to clean and sanitize compared to standard beer kegs.