I like to use the zoo-med moss from the pet stores. Its a moderatey tolerable blend of long fibre and medium fibre new zealand shpagnum while not being 5A. Its really clean and if you treat it well it will start to grow fresh live sphagnum.
most other mosses to me is very dirty and it smells of ammonia to my big nose when the moss is wet...
I spend a lot of money on my plants. I want the best for them that I can afford. I dont be cheap with the moss.