I had United Healthcare for first year after being diagnosed. They were really good about covering my remicade and other medications, but were very difficult about an emergency hospitalization that I had due to a blockage. It took them 2 years of fighting with a hospital counselor to cover it as medically necessary.
I have since switched to I.H.C. Select Med and love it. They actually paid the disputed hospital stay twice even though it was from before I was covered by them. The hospital counselor kept having to send them a refund because United was the one that was responsible. I have not had any problems having to qualify for any of my surgeries or procedures either.