Last week, in Boston, my wife and I did an erg "taste-test", to see what the differences are in feel between all the lastest ergs. We hopped from one erg to the next to try to get a somewhat obejctive feel to the differences in machines. FWIW: my wife was a triathlete turned rower and I am a rower turned triathlete, so we both have a little experience and know how to "operate" ergs.
The new dynamic c2 is just ok. The seat is actually "anchored" with an elastic cord, to prevent "too much" range. It can be unanchored. I still found this strange, and almost like an afterthough in the design. The flywheel does not move, rather the handle moves (on a cable, now, not a chain) and the footstretchers move (also connected to a cable, not a chain). The rail on which the seat slides looks shorter than the 80cm tracks used in most singles. So it looks like c2 found a way to rethink their erg, and not rethink how to simulate the rowing motion (the call their machines "Indoor Rower" and not rowing ergometers, now). Rowing on the dynamic c2 erg feels like rowing on sliders, but "tighter"; sometimes the erg feels like it coasts a lot, when on sliders, and slightly less so on the new dynamic erg. The new erg is still pulling a handle and pushing the footstretchers. So a marginal improvement in design and feel.
I've spent a little time on the RowPerfect, and it is closer to the feel of rowing compared to a static erg, since the flywheel slides on the same rail that the seat does. It requries good technique, and the dynamic feels "closer" to rowing since one is moving the flywheel and sliding, as opposed to just trying to spin the flywheel and rely upon air resistance for load. The RowPerfect is a great tool for workouts and keeping technically sharp. It's expensive, esp for non-rowing athletes.
The OarTec (
http://www.oartec.com) is by far the closest thing to rowing--so far--without getting into a boat. Both my wife and I, independently, felt that the OarTec felt the best, by far, of all the dynamic/sliding ergs, and if were were going to buy more ergs, this would be it. She's working with oartec to get a demo erg for our club. I took video of her rowing on it and it was quite evident that the erg slides, and the athlete does not. This is what *should* happen. This erg felt the smoothest, the loading did not have a slack feel at the catch (like the c2 does). She tried it again two days ago, in Philly, and she her pair partner were able to really crank it down to some impressive splits, with less perceived--or apparent-- effort than a c2. They both said that it was much easier to get the erg moving faster and keep it moving, than the c2 or c2 on sliders, since they could "row" it, instead of just trying to tear the handle off. The cost of this erg is the same as a c2 w/ sliders, or the new c2 dynamic erg.
I have NO interest in c2 or oartec: but if you're gonna spend money on an erg, get the oartec.