It really just depends on what moves provide more coverage. Need Fire, Rock, and Grass (or see Tailwind + Water Urshifu)? Go with Sneasel and Coalossal. Need Steel, Fighting, Rock, and Flying (or see Tailwind + Dark Urshifu)? Go Sneasel and Cobalion. See G-Weezing? Go Gastrodon and Cobalion. See...