The elliptical is one of the very best because it's good for cardio and has the advantage over most other machines in terms of both low impact and the perception that the exertion is "easier" for the same amount of work.
Bottom line use whatever inspires to use regularly, as long as it doesn't cause injury.
Bike's not on the same level as the others unless a very rigorous spinning type intensity's used. Rowing machine's quite good, so is treadmill if there's no aggrevation from use.
Different ellipticals from different companies-you've never heard of competition? LOL IMO the Precor and Arc Trainer are the best but most of the gym versions are good.
