another high level rower chiming in:
concept2 is definitely the standard and is probably the easiest to find, both used, as well as replacement parts.
oartec makes probably the best erg i've ever used - it is much more technique driven, it is basically a concept2 on sliders. i'd imagine more expensive.
i'd advise you to look for a Model C if you can find it - D & E are really just fancier monitors, and slightly more comfortable handles. you can upgrade either of those parts, if you want, but no offense - i don't suspect you'll use it enough to appreciate the difference.
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@adamwfurlong
concept2 is definitely the standard and is probably the easiest to find, both used, as well as replacement parts.
oartec makes probably the best erg i've ever used - it is much more technique driven, it is basically a concept2 on sliders. i'd imagine more expensive.
i'd advise you to look for a Model C if you can find it - D & E are really just fancier monitors, and slightly more comfortable handles. you can upgrade either of those parts, if you want, but no offense - i don't suspect you'll use it enough to appreciate the difference.
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@adamwfurlong