There is some minor maintenance. Because it's made out of wood, which can expand and contract, the bolts need tightening every few months or so. It's easy and takes only a couple of minutes. That, and putting in a fresh water purification tablet every six to twelve months, are about it for regular maintenance. The only problem I've had with the rower (the reason for 4 stars instead of 5) was a squeak that developed after about 6 weeks. It took me some time to determine the source of the squeak, which was a metal bracket connecting the footrest board to the horizontal boards above the drum. I had to partially disassemble the top section and tighten four bolts, but that fixed the problem and it's been quiet ever since.
Rowing is one of the few non-weight bearing sports that exercises all the major muscle groups, including quads, biceps, triceps, lats, glutes and abdominal muscles. The sport also improves cardiovascular endurance and muscular strength. High-performance rowers tend to be tall and muscular: although extra weight does increase the drag on the boat, the larger athletes' increased power tends to be more significant. The increased power is achieved through increased length of leverage on the oar through longer limbs of the athlete. In multi-person boats (2,4, or 8), the lightest person typically rows in the bow seat at the front of the boat.
The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.