We use and recommend a counterflow chiller over immersion chillers and plate chillers as we feel they are the best compromise between performance and ease of cleaning while minimizing limitations on how or what you can brew. With a counterflow chiller small portions of wort are chilled instantaneously from boiling to yeast pitching temperature. This locks in hop flavour and aroma and limits excessive dimethyl sulfides (DMS) which can cause a 'cooked corn' taste and aroma in beer. It also helps ensure that cold break comes out of solution eliminating 'chill haze' issues once the beer is refrigerated for serving.
While stainless steel has a lower heat transfer coefficient (i.e. is less efficient) than copper, this difference is negated by the fact that our stainless chiller uses 29.5' of tubing instead of 12' as found in the copper version.
For more information and recommended fittings / attachments, see our Wort Chiller guide.