As I mentioned, the rowing experience with the WaterRower is amazing. I bought the rower for myself, but my wife was curious and decided to try it out. She loves it, and now rows almost daily. We have a treadmill that neither of us has used since we started rowing - the WaterRower is a much better workout and much more enjoyable at the same time. It's easy to adjust the intensity, pace and duration of your exercise. There is nothing to change on the rower (* see note below), you just row harder or faster, adjust how far you lean forward and back during your stroke. The WaterRower will keep up with you as your fitness increases, all you need to do is keep throwing more and more at it.
However, I own an air rower and have zero worries about maxing out it’s ability. I can completely exhaust myself on any type of workout. Air and water rowers are the chosen resistance type by Olympic athletes and any athlete looking to train their full-body cardio. I don’t think they would choose this resistance type if they felt they could max it out.
Con's: Super bummed that for $1160 they couldn't include an internal ANT+ transponder and Heart Rate strap(sub $100 package). The foot straps are crap! Within the first 1000m of moderate rowing they loosen to the point of being able to pull foot out on Recovery of stroke(Yes, even with ball of foot down). I really wish the WaterCoach F.I.T. software for the S4 Monitor was macOS compatible. It'd be nice to able to customer program workouts on my MacBook Pro or iMac.
Rowing has long been recognized as the perfect aerobic pursuit, with naturally smooth and flowing movements that don't tax the joints but do boost the heart rate. Now you can take your rowing experience to the next level with the WaterRower Natural rowing machine. Using the same principles that govern the dynamics of a boat in water, the WaterRower Natural is outfitted with a "water flywheel" that consists of two paddles in an enclosed tank of water that provide smooth, quiet resistance, just like the paddles in an actual body of water. As a result, the machine has no moving parts that can wear out over time (even the recoil belt and pulleys don't require lubricating or maintaining). More significantly, the water tank and flywheel create a self-regulating resistance system that eliminates the need for a motor. As with real rowing, when you paddle faster, the increased drag provides more resistance. When you paddle slower, the resistance is less intense. The only limit to how fast you can row is your strength and your ability to overcome drag. And unlike conventional rowing machines, which tend to be jerky and jarring, the WaterRower Natural is remarkably smooth and fluid.