what label for the middle ages best describes the era between 500 and 1400 in europe: the dark ages, the age of feudalism, the age of faith, or the golden age of europe?

I'd say the Dark Ages is the best description. Rome fell in 1000 C. E. and after that, everything got worse and worse. The Black Plague was also in the 1340s. No guarantees, feudalism was also around during those years.