There is much to love about the WaterRower--and I do love it--but I would echo others' comments that although the seat rolls solidly and smoothly on the wood rails, the seat itself is very hard (I use a gel seat pad I bought for my hard fiberglass kayak seat), and the footpads are in need up rethinking and upgrading--the cheap plastic doesn't let you row in socks or barefoot and is not really worthy of a machine that is otherwise a stunning piece of engineering and a beautiful one as well. As one other person noted about his machine, my machine made a clicking noise on the return stroke, so I had to adjust the wheel underneath the top rail that connects to the footpad and pull it away gently from where it was rubbing against another component. Also, be warned: the instruction booklet is in the DVD case. I did not see the little sticker on the case telling me that, thinking I'd wait to watch the DVD until after I'd assembled it. But WaterRower has a copy of the assembly instructions on their website, along with a video (I found the written ones better and easier to follow), so I was able to assemble it with no difficulty.
The Challenge AR has the capability to allow the rower to control and adjust the resistance from “Feather light” to “Olympic sprint” delivering a silky smooth resistance to the user’s effort and instantaneous response to input with no “flat sport”. With water resistance being the most accurate manner in which to simulate actual outdoor rowing, the Challenge AR provides a smooth and consistent sensation throughout the range of motion of the exercise experience.
First of all, if you're considering rowing, just do it. It is by far the most enjoyable and beneficial exercise I have ever tried. I've made huge strides with both cardio and muscle fitness with the WaterRower, and it's so enjoyable I look forward to exercising each day. Yes, it is more expensive than most other rowing machines, but when you compare it to a lot of other types of exercise equipment, it's actually pretty reasonable. When you also compare the exercise benefit you get, it's a bargain.
The WaterRower Natural is outfitted with a Series 4 performance monitor that's designed to balance technical sophistication with user-friendliness. The monitor--which includes six information and programming windows, six QuickSelection buttons, and three navigation buttons--displays your workout intensity, stroke rate, heart rate, zone bar, duration, and distance. Plus, the monitor is compatible with an optional heart rate chest strap and receiver, which helps you optimize your workout and achieve your exercise objectives.