Concept 2 is indeed the cheaper and better option for an erg. Aside from being very sturdy machines at reasonable prices compared to your nordictracs and pelotons, old models are supported essentially forever with spare parts and detailed installation/fix instructions. I dont know of any rowers who don't swear by them.
I picked up a model A for just this reason. $120 on craigslist for a 35 year old machine. It is super solid, but will need to replace a few minor parts soon. And from what I can tell they are all available for purchase from concept2, which is awesome.
