Being able to easily store your rower is a huge plus. Make sure you investigate how well the machine stores, if it folds up or comes apart easily to be able to put it in your closet, or in other storage areas. As an example, the Concept2 Model D rowing machine folds up nicely by a simple pull pin located in the middle of the rower. Wheels on the bottom allow for easy moving.
The reason I'm writing now, two years after purchase, is, I broke one of the wheels. I proceeded to order the wrong replacement, so I emailed them pictures to ask for the right parts. They wrote back asking for the serial number to get the right unit AND to see if it was under warranty. (Hadn't even occurred to me.) Turns out it was, they're sending me the wheels, they're refunding me for the wrong part, AND included a link for the Puri-Tabs which I didn't know they provide for the life of the ROWER! They're also replacing all eight wheels even though there's only one broken one.
Note: Some states do not allow limitations on how long an implied warranty lasts, so the above limitations may not apply to you. Some states do not allow the exclusion on limitation of incidental or consequential damages, so the above limitations or exclusions may not apply to you. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.
Essentially, the water rower uses water as it's resistance and the air rower (click here to read our air rowing machine reviews) uses air resistance. Additionally, the resistance of the water gives a very similar feeling to actually rowing in the water. The rowing machines listed above all have fantastic rowing mechanisms that mimic the exact feeling of a rowing a boat.
Other details include dual rails with four corner wheels that increase seat stability and reduce the amount of sweat buildup; a frame that flips upright for handy storage; and a weight capacity of up to 1,000 pounds. The WaterRower Natural measures 84 by 21 by 22 inches (W x H x D), weighs 117 pounds (with water), and carries a one-year warranty on the frame and components (WaterRower will upgrade the warranty to five years on the frame and three years on the components with the completion of a registration form).