Training & Nutrition - Schwinn Air-Dyne

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I've had a Schwinn Air-Dyne for many years, not used as much as it should be. Just wondering on opinions as to how effective it is for winter training? I'd think it's good cardio training, but the pedals seem to be a much different angle than my mountain or road bike. Wondering just how effective it is in keeping my legs in shape for the "real" bikes?
May be useful for fitness, but not useful to replicate road cycling experience. I've had one for years. Haven't used for years. But the whole lower body, upper body, built in fan thing is a good deal for in-home exercise.