Epic OU Battles of Historyyyyyyy!!
+) Wicked speed, one of the fastest non-Mega Pokémon
+) Great ability in Volt Absorb
+) Good Sp. Attack
-) Poor movepool
-) Garbage HP and Defence, with passable Sp. Defence
-) Weakness to the omnipresent Earthquake
Jolteon is the hard hittin', Thunderbolt absorbin' speedster you all know an love. He also looks awesome. He has a rediculous 130 Speed stat, enough to outpace even most Megas, and a decent 110 Sp. Attack stat. Volt Absorb also lets you switch into Electric attacks aimed at your Gyarados or Talonflame and heal back some HP. Unfortunately, that's about where the positives end. Jolteon's Special movepool is pretty much Shadow Ball, Thunderbolt, Signal Beam, and a Hidden Power of your choice. Maybe Helping Hand. On top of that, you are pretty much forced to run Focus Sash with his middling 65/60/95 defences.
+) Has respectable 90/85/100 defences
+) Offensive stats aren't too shabby either, sitting at 115 Sp. Attack and 115 Spe
+) While his movepool is pretty shallow, it's better than Jolteon's
-) Mediocre movepool
-) Weakness to Earthquake
Raikou, everyone's favorite thundercat (shutup Luxray). He has a near perfect distribution of stats, not weighing too much on bulk or offense. He can effectively run Life Orb, Assault Vest, or Choices Specs sets. While not as fast as Jolteon, he still outspeeds a heckuva lot of Pokémon at base 115. His movepool is both one of his strengths and his greatest fault. It's limited to Thunderbolt, Hidden Power, Extrasensory, Snarl, Shadow Ball, Signal Beam, and Light Screen. However, he can pull off a lot with just those moves. Pseudo-boltbeam in Thunderbolt + HP Ice, flinch hax with Extrasensory, and coverage with Shadow Ball are his main attacks, rounded off by Assault Vestor Choice Specs. His support movepool is barely passable, holding just Thunder Wave and Light Screen, but the niche is there. In the Doubles format, Raikou will often find Shadow Ball or Extrasensory replaced with Snarl to lower both opposing Pokémon's Sp. Attack.
Raikou is most definitely the winner here. While he lacks a bit of the speed and power that Jolteon brings, he more than makes up for it in bulk and utility.