The PET carboy is easy to clean because it is hydrophobic, so a soaking solution of Five Star’s PBW (Powdered Brewery Wash) usually does the trick to clean up the fermenter. They are easy to grip when wet and much easier to lift when full and wet. And, because they are unbreakable (e.g. pouring hot wort into a cold carboy is not a concern for shattering a plastic carboy, but is for glass), they provide one less reason to go to the local emergency room.
So, I am a bit prejudiced on which carboy you should use. Here’s Northern Brewers take on the pro and cons of each:
The Tap-A-Draft system is a reasonable compromise between the drudgery of bottling and the ease of kegging. Each of the three see-through plastic mini-kegs holds 6 liters (1.58 gallons or 203 ounces) of liquid. The three bottles can hold 4.75 gallons of product. It costs about $70.
You don’t need a second refrigerator to hold it. In my refrigerator it took up about one-third of the lower shelf. That’s a significant displacement, but not ginormous. The bottle is 12.5″ long, and 7.5″ in diameter. The dispenser spout adds 4″ to the length.
You can force carbonate beer or soda, and drink it darn-near immediately.
The dispensing valve has two built-in regulators that maintain a constant 15 psi.
You have to fill three bottles only, instead of 51 12-ounce bottles.
The CO2 cartridges are easy to handle and change out.
The dispenser has a one-way check valve to keep CO2 in the bottle.
Pressure relief in case of excessive pressure. If the pressure in the bottle exceeds 60psi, the valve opens to release the pressure in the bottle.
The valve carries a one-year warranty against any manufacturing defects.
The dispenser valve is not spring loaded.
You must ensure the valve is completely closed and the locking tab is securely in place, otherwise it will drip. I have lost three gallons of beer in a span of two weeks. (Yes, it is “operator error” but it requires a boatload of diligence to keep it from happening.)
Because, I have now suffered two dispenser valve accidents and lost some darn good beer (My L’il Sumpin’ gone–I was tempted to lick the floor), I’m going to use fill only one Tap-A-Draft bottle and put the remainder of the beer in 12-ounce or 22-ounce bottles. Your mileage may vary.