Check your total out of pocket costs for deductibles, prescriptions, etc. between the choices. Be sure that the changing coverage would allow you to use the doctors and medical facilities you prefer.
Dittoes on the above advice. Especially with regards to the deductibles. IIRC, I was reading yesterday about some goober going for the Silver Plan only to learn the annual deductible was THIRTEEN THOUSAND DOLLARS!
(Holy Crap)