I have an affiliate link only site in a gift niche. It has been live for over six years. While not at the top of the pile, I have decent rank for very competitive keywords - up against big brands.
For years my affiliate links had no no follow on them, and for the last six months they have had no follow on them. No difference in ranking. And for years they were uncloaked, and for the last two years cloaked - no difference in ranking.