I have the 50' stainless model. It works great for me. I can get a 5 gallon AG batch down to 80 in 15-20 minutes.
In another thread someone suggested that stainless steel being a stronger metal than copper the walls(of stainless steel IC) are a bit thinner making it more on par to copper's efficiency.
Secondary 1 - Hibiscus Saison
Secondary 2 -
Secondary 3 - Malkore's Not So Ancient Orange Mead(2.5 gal)
Secondary 4 -
Gallon Fermentor - Joe's Ancient Orange, Joe's Quick Grape Mead, Pomegranate Mead
Bottled/aging - Sunshine Wheat Clone, Fat Tire Clone, Hard Cider, Scotch Ale, Orange Blossom Sweet Mead
Coming soon... - Weizenbock, Belgian Wit, Apfelwein