I tried some Fermcap S yesterday for the first time and am impressed. I brewed Tasty's APA and pitched about half a yeast cake of Pacman from another beer I had just racked. I got a call from work right when I pitched and had to leave for a while. I was figuring on pumping some O2 into the wort when I got back.
I got back to it about 3 hours later and fermentation was rolling like crazy.

Foam was crawling rapidly towards the airlock. At this point I would ordinarily be scrambling for the blow off tube. Instead, I added 12 drops of Fermcap S (5.5 gallons of wort). The rise of the foam stopped and by morning there was only about about an inch of foam left yet the airlock was chugging away like a steam engine. I just may be able to retire my blow off tube. That thing is a pain to clean anyway.
Wayne