These are things I have heard, and a thought. Some say suede is bad, others say it doesn't matter. In either case, chrome tanned material is a no go. The reason suede is frowned ed upon, is because it has a course surface that will hold dust and dirt, causing abrasions on you pistol surface. Using this course of logic, felt would also be bad.
I have used suede in only a couple of holsters, and not heard any complaints yet.
I regularly use plain veg tanned leather, either 2-3 ounce, or even 6-8 ounce, always grain side up. Others I know, prefer pig skin. In any case, you shouldn't leave your pistol in its holster when not being carried, and clean/oil regularly.
Your mileage may vary.