Does any one here use a rowing machine? Is it best for aerobic exercising, or more for muscle work? I ask, because I have tried a rowing machine a few years ago, it's one of the cheaper sliding like ones, but I found it fun (better than the stn. bike, weights, and the treadmill this small gym had). I did not lose weight at the time as I was diagnosed hypo-thyroid about a year later, so my weight was slowly going up. I only used the rower about 20 mins. at a moderate pace. But now that I'm somewhat stable on the thyroid pill, I would like to get back into more of an aerobic shape. Currently I do yoga (very limited aerobic wise), and walk. Also, there's supposedly dif. types of rowing machines. Has anyone here tried dif. ones, and can recommend the best? Or would an old fun (cheaper) one suffice (for someone like me who's more or less just starting out). Any insight would be greatly appreciated.