I’ve used both at various hotels and gyms, but owned neither and I’m not a big rower so perhaps I’m not the best judge. In my opinion the water rower is nicer to look at by a mile. It almost looks like a nice piece of furniture. And the wood comes in different stains to match your decor. It’s also way quieter in use and feels a little more like rowing an actual boat. If I owned a fancy wood panelled home gym with big windows looking across my boating lake I’d have a water rower without a shadow of a doubt (alas, I own none of the above!) Though with that said I think the c2 is the gold standard for a reason. The water rower is a luxury item, and needs some maintenance. The c2 is nukeproof and works fantastically.

Also the c2 is in every gym and loads of people use them, which means you can compare notes against people and be taking about the same thing which is cool. Loads of pro athletes including rowing teams and clubs use the c2 - they can’t all be wrong!