B.B.
I can't offer any information on Great West, but I work for a doctor and handle all of the office's insurance billing. It has been my experience that United Health Care is one of the most difficult insurance companies to deal with. They do everything possible to avoid paying claims, including losing the paperwork and claiming that current, accurate codes are incorrect. This is just my experience. If they are the company that makes the most sense for you financially, then I would suggest just being extra sure about what you are getting, which docs are covered and to what extent. You may have to keep a closer eye on them to get claims paid.
Best of luck to you and your family!