Originally Posted by
Mabouya
IMO the single biggest technical & performance difference is that the C2 ergs have a more sophisticated way of calculating the work done and your pace. (it's based on the drag, measured during the spin-down of the flywheel). The C2 air-drag also gives you a smoother increase at high power levels, whereas folks say that with the WR you "hit a wall" and just can't do any more. (If you Google "concept 2 rower vs water rower" there are quite a few comparisons online, some of which discuss this.) In general the C2 PM is a better, more capable unit than the WR.
Bottom line, based on what I've read, for casual users who don't prioritize "serious athlete" factors, and are more interested in aesthetics and noise level, the WR is fine, but if you want to push yourself and demand more from the machine, the C2 is almost certainly the way to go.
Caveat: I've never used a WaterRower