In reply to Denni:
I trained a lot on a Concept II for years. It cost me around £800 new and that was 20 years ago, but they’re worth it (as mentioned, look for second hand if you can’t justify new). They’re reliable, you can buy parts if needed (I did 80,000m a week and there was no sign of wear after years of use), and they’ll take your weight and height easily (although heavyweight rowers tend to weigh down the front legs to stop it moving). You really only need to wipe down the rail with a cloth after a session (10 secs) and occasionally lubricate the chain (30 secs). There are indoor rowing competitions and I’m sure you must still be able to do time/distance trials at home and submit your results to CII for their rankings, which helps to keep interest (Olympic gold medalists - Redgrave, Pinsent, the Searle brothers etc - were all in the ranking lists when I was rowing). And speaking as someone who also did athletics for years, it’s a brilliant cardio workout (whether short intervals, long distances etc) and far less damaging to the body.