I have used the spigot on my Spiedel 30L to transfer beer from fermenter to keg several times recently. In a nutshell, the spigot is easy to use with a fast clean transfer.
First, I spray the spigot with starsan. Next, I attach sanitized 1/2" ID vinyl tubing to the spigot and let her rip.
It's so fast I overflowed a keg when I turned my back for 1 minute a few days ago. The wife was not pleased.
The transfer grabs a few bursts of yeast when you first start. If you don't jostle the fermenter while transferring, you get clear beer in the tubing after about 1-2 seconds of yeast. When taking the first draft from a keg I still get clean beer after dumping the first half pint.