BIG advantage is they ignore pre-existing conditions, which is then also carried over when you leave EK and the cover can be continued (at market rate)..at least you then have cover you might not have otherwise had.
I hear there are better schemes out there (cheaper) that some have access to, but none available to me. With the seemingly ever-increasing preference of EK's personnel management to deny claims where possible, having Aetna in my back pocket is a weight off.