That was my at home gym when I was weller than I am now. I can't get up from it anymore.

You can get a darned good workout if you want to. My habit was to keep up with fast music for the duration of a CD. If you plan to get serious, keep a clean towel under it to preserve your carpet.

I found a pretty comprehensive buyer's guide here:
http://www.mens-total-fitness.com/rowing-machines.html

Dangit, Snoopy, you have me thinking about another one and I have no idea whether I'll be able to get off the bugger!