I honestly don't know, but it looks like both use mostly off the shelf parts. From what I have looked up the Free Flow Sport, is a series not a specific tub, the current round tub in the Sport series is the Aptos which is a 78 inch 290 where the Viking V-100 is a 72 inch 240 gallon. While I know it is not always the best way to compare things, if you go down the spec list it seems the FreeFlow wins on every point: more jets, bigger pump, more features (light, covertible to 240V for more heat if needed (1KW at 120V or 4KW at 240V, where the V-100 is 120V 1KW only).