All the addons are basicly doing the same: making it possible to heal using some sort of raid frames. It fastens targetting and therefore healing. Since healbot, Vuhdo, grid + clique, etc can do it, there is no diffrence in being the best addon. One might argue that you have this option or that option more in one addon, but all these can be done by other addons. The basic of a healing addon remains interactive raid frames.
So picking the best one, just means pick the one you like the most considering esthetics, additional features, etc.