I need info about marcy exercise equipment?

Question

in particular a stepper on one side and a twister on the other

Answer 1

Marcy exercise equipment, including the stepper/twister "thing" you are referring to, is on par with the low end garbage pushed by Weider and isn't worth much time investigating.

The ergonomics on this machine are terrible and give it a 'cheap' feeling.  When manufacturers try to produce a functional piece of exercise equipment in this price range, they have to make compromises in material quality and adjustability.

Try some higher quality pieces of equipment by Bowflex or Powertec.