Highmark Inc. is facing its first real competition in the Western Pennsylvania health insurance market. But the extent to which that competition has resulted in lower costs for employers and lots of new business for four national, for-profit insurance companies has been limited so far, said a consultant. "They have their toes in the water, but they're cautious," he said of the approach to the market by Aetna Inc., Cigna Corp., HealthAmerica and United HealthCare.