Slaking Is Incredibly OverPowered
Believe it or not, slaking is actually the greatest Pokemon in Pokemon GO in terms of its Maximum combat power Level, coming in at a remarkable 4548. Not even one of the legendary Pokemon, whether presently released or is yet still to come, even reaches such a mark! Slaking has a ridiculous combination of Stamina, Attack and Defense because of this, allowing trainers to use it as both a fierce Gym Attack and viable Gym Defender!
Between the two, however, primarily because of its Stamina and Defense Stats, slaking makes for an even greater gym defender. This also has to do with Slaking having Yawn for its only Fast Attack, preventing it from doing anything outside of Special Attacks (and having to wait with no other attacks in between). However, even with this crippling albatross, since its extremely high combat power Level, Slaking is almost impossible to defeat with just one gym attacker. Thus, Slaking is widely considered to be, at least in this Pokemon Game, overpowered in every single regard!
If you ever get the chance to evolve your vigoroth into a slaking, do not take one second to think about it - Evolve it!