As an avid user of Jolteon in DPP, it amazes me how this thing isn't as used as much as other OU Pokemon. Outside of Blissey and Snorlax, there are very few ways of actually taking this beast on. I don't see how that makes it any different from other Special attackers though, Blissey and Snorlax wall pretty much all Special attackers (NP Infernape is pretty much non-existent at the moment) Once these special walls are gone, Jolteon has exactly 0 safe switch-ins. Blissey and Snorlax are easy to get rid of anyway. Jolteon is very effective when used with the correct team support due to the fact that it OHKOes/2HKOes pretty much everything that's not named Blissey or Snorlax. Outspeeding +1 Adamant Gyarados (much more common than Jolly Gyarados) is pretty huge as well. It also outspeeds +1 Adamant Dragonite, but this is nowhere near as relevant because Dragonite can just use ExtremeSpeed. Despite its frailty on the physical side, its resistance to Bullet Punch is pretty useful.