It should improve my overall fitness if I used it more vigorously!
Concept2 is the gold standard. Buy and resell years later for most of your money (esp. since it's a Crossfit type staple), and you can get parts for every model they've ever made! I think it autocalibrates on the coast down so your workouts are always normalized, whether on your personal rower or at a health club or rowing club anywhere.
One of my friends is looking at a water rower, but I don't know much about them other than they can be much better looking than the Concept2.
Interesting article about Concept2 vs. WaterRower http://www.jamesstroud.com/postings/c2-versus-wate...
Funds unlimited it seems like it'd be better to get one that simulates kayak or canoe stroke to be more AR specific. Bash may have one?
Currently I think I mostly use it to enhance misery tolerance, as in, >1 hr on the rower = lots of mental toughness, esp. in regards to sitting on a slightly uncomfortable seat. It's the hardest piece to stay on the longest, I think. (bike trainer = easiest, treadmill next, elliptical, then rower for me). I should try to get to a higher heart rate more than I do - I'm not a terribly disciplined person. Also, I can freely erg away any time I'm worried I've worked my shins running - no pain or anything for me.
Mine is a $50 Salvation Army-acquired Schwinn, using a fan for resistance with some sort of belt to pull. It is a bit noisy, and the biggest reason I run wireless headphones for after hours exercise, so as to not have to crank the tv while others sleep.