I believe the Nitro, besides the aesthetics, is also the only one with overengineered cooling. So the question of the prices difference really should be the question for amount of noise it makes (fan wise) and how much heat both you and the GPU can tolerate when the environmental temperatures creep up during the summer. If it's fine (you use Air Con for example), then I don't see why you need to go for the Red Devil or Nitro, the basic default at that point will be fine if the sound level is OK for you.
But if the nosie and temps can be a concern, then the Red Devil and Nitro are your better bets are not sitting next to a heater when in use during the summer. (Thinking about it now, that's probably what helped contribute to my older rig dying, as it happened right after the 40C heat wave in London last year). Anyway, all good cards in any case.