I'm an insider (supervisor at a big health ins co). Here's what most people don't know. The carrier has little to do with anything. Most accounts are ASO now (administrative services only). This means that your company has a bank account that claims are paid out of. They set the benefits, etc. Then they pay a company like one of the above (and no, I don't work for any of these) to process claims, provide customer service, contract providers, etc.
The insurance company doesn't make decisions... they just implement the rules specified by the company who has contracted them.
Thus, read the plans for all three. Determine what you need, how much you will use it, what you'll use it for, etc. Realize that for people with major illnesses, often managed care (copay-based plans) end up costing more than PPO-type plans (deductible-based) because, as soon as the out-of-pocket is met, you don't pay for any more services.
As I said, this varies by plan. So, do your homework and you'll make the right decision and save money.
Anyone who says premiums are cheaper with one company or another is speaking from their experience at their company. Insurance companies managing ASO accounts don't collect premiums. When you pay a premium, you're making a deposit into the account that your company has its claims paid from. Thus, you're paying your employer, not your health insurance company.