I have used the Gigawort and Biab for about 40 batches and it has worked out great for me. Because it's a smaller size than the other one on the market, the max volume is around 4 gallons/15 liters. There is about another 1&1/2 inches above of head space to the lid. 8 liter batches would be perfect on this system. I do short mashes, no sparge and and short boils and typically finish with 11 liters after boil.
I usually use around 5 lbs of grain and start with 14 liters of water. I've pushed it to 15 liters and 5.5 lbs of grain but I had some issues with the wort seeping over the edge through the bag with it being this full.
The delayed start feature is great for heating up water to have ready for either when you get home from work or to start up first thing in the morning. Some say that the temperature reading is off by a couple of degrees. Just use another thermometer to double check your mash temp.
Just a heads up, this is a really basic kettle, there is no pump, no mash basket or chiller included like other brands have. With that said, I have really enjoyed using it. Smaller batch brewing makes for quick brew days and really easy clean up.
