>>58931817Best Eeveelution tends to vary between games a lot, and also tends to come down to how much you are willing to invest in the mon.
Take Gen 4 Sinnoh for example.
Jolteon and Flareon get easy access to Thunder and Fire Blast, but both are a bit frail and really don't like missing- and the only way to get Thunderbolt and Flmaethrower at a reasonable point is the game corner.
Vaporeon gets the always reliable Surf, but really late, so it is stuck using Blizzard.
Espeon is ass unless you invest in the Game Corner Psychic TM(and they are expensive!).
Umbreon gets immediate access to Payback as an accurate 150 BP move after STAB, giving it at least one solid attack move to spam.
Leafeon is an oddball who doesn't get access to any good grass moves, but its Return is about as strong as Umbreon's Payback, and Leafeon is both bulky and fast. Leafeon can also hit the Game Corner like the others, picking up Sword Dance for less than half of what Jolteon, Flareon and Espeon is spending.
Glaceon is basically not available with the shitty placement of the Icy Rock.
The best might be Jolteon even with the accuracy issues, but you have a better Jolteon already in Sinnoh with Intimidate attached.
Flareon has a case thanks to Choice Specs arriving at a reasonable point and it having better accuracy than Jolteon.
Leafeon and Umbreon are both solid.