Jolteon

The once-and-former best Electric Type of Pokemon Go's debut, Jolteon has not aged well in the slightest. It's good for players just starting the game, as high-level weather boosted Eevee tend to be everywhere, making it a strong budget option. However, it's also very quickly outclassed by most 0-IV Shadows and Legendaries, as well as many normal species such as Magnezone and Electivire. 

Best PvE Offensive Moveset

• Thunder Shock is the better fast move, with a lower cooldown, faster energy gain, and similar DPS to Volt Switch.

• Thunderbolt has slightly better damage output than Discharge. Jolteon will also spend less time in cooldown with Thunderbolt.

• Thunder is too weak for requiring a full bar of energy.

• Zap Cannon as a 1-bar move is strong but less consistent than multi-bar moves. 

• Last Resort* has little to no offensive viability.

Best PvE Defensive Moveset

• Volt Switch's raw power and energy gain are ideal for defense.

• Discharge and Thunderbolt are once again comparable options. Discharge is more likely to be used before Jolteon bites the dust.

• Last Resort* hits Ground-type counters much harder, but it's also really easy to dodge. 

• Thunder is the hardest of Jolteon's charge moves to dodge, but Jolteon might faint before it can use it.

• Zap Cannon is too slow for defense, unless the attacker isn't paying attention. 

While Thunder Shock doesn't have as much raw damage output as Volt Switch, the significantly higher energy gains easily make up for this. 

Of all the options Jolteon has for its charge moves, Discharge stands out as the cheapest option in terms of energy, which also makes it the best option to bait shields. Thunder costs only 5 more energy than Thunderbolt, but deals more Damage Per Energy (DPE) which makes it the more valuable pick. Last Resort could be an option to deal neutral damage should Electric-type damage be resisted, but the lack of power and STAB causes Jolteon to lose way more matchups against most of the meta. Zap Cannon demands way too much energy to be consistently viable.