If I were an insurer, I'd wait a year before entering the exchange market. All the headaches, for little profit. Let someone else fall on their face, and pick up all the unhappy clients in year 2. Article has insight from the top insurers approach
Big Health Insurers Aim for New Exchanges, But Cautiously - WSJ.com
Big Health Insurers Aim for New Exchanges, But Cautiously - WSJ.com