Here is a free plug for this rowing machine. I have had a couple of serious trainers tell me this is the best overall aerobic machine. I still prefer spin class and the elliptical is still more congenial. But I bet those trainers are right.
Most interesting to me…it seems clear that it calls on slightly different muscles (and aerobic capacity) than biking. Even though it is 70% legs. Also, lots of core. I intuitively believe that I could use more and more of that as I get older. So ROW! Not as much fun but maybe good for us.