In CO, C-sections are covered by state mandate. Coverage for complications is VERY limited and varies by state. Also, it does not include complications for the baby - as in NICU etc. I would not count on it for much.
Humana is a well respected company but I am sure they have their share of complaints as well - just like any other carrier. I don't know anything about the senior market, it's not an area I work. I just got appointed with Humana individual products this year and have no information on how their rate increases are - again, this will vary by state/region.