Count me as another happy customer using the Williams O2 metal aerator.
It works as advertised and I swear I notice quicker and stronger fermentations since using it on both my starters and wort pitches.
Secondary/Lagering:Oktoberfest & Doppelbock,
Bottled: Am. Amber, ESB, JC Dubbel, Behemoth Imperial Stout, Wee Heavy Scotch Ale, Lefty Vienna Lager, Hefeweizen, Sm. Barleywine, Sm. Porter, Dunkelweizen & Helles Bock, Nut Brown, Cream Stout
Kegged: Trippel, Cream Stout, Belgian IPA '13, Nut Brown Ale, Am. Amber, Hot Walker Pale Ale