134 Vaporeon

Water Gun is a good move and Vaporeon's only Quick-Move option with 3 DPT (Damage Per Turn) and 3 EPT (Energy Per Turn).

Aqua Tail gives Vaporeon an quick-charging, decently powerful Charge Move to spam frequently. Scald received a buff following the GBL Season 9 update and is now more viable as a secondary move. Since its chance to debuff the opponent is only 30%, this is not a consistently reliable strategy, though Scald does deal more Damage Per Energy (DPE) if unshielded. Hydro Pump demands a huge amount of energy to use, making it less desirable. 

This set foregoes the power of Hydro Pump or debuff potential of Scald to give Vaporeon an option in particularly bad matchups via the aptly named Last Resort. It can provide better power VS Grass, Dragon, and fellow Water types, though against Grass types in particular it's probably best to try to get Vaporeon out ASAP.

Despite its defensive stat-build, Vaporeon has no real use in the Great League. It's simply outclassed by other Water types.

Vaporeon is a capable Pokemon in the Ultra League, combining good bulk with a good overall moveset to be fairly effective within its own niche. However, its type coverage leaves much to be desired, and it's definitely outclassed by a number of other great Water types in the tier, making justifying adding it to a team a bit hard.

Vaporeon's bulk comes into its own in the Master League, making it a surprisingly powerful option for the Master League. However, it's still outclassed by many other water-types, with Kyogre in particular beating it out badly.