I'm going to give wither Pokemon choice specs with the moveset being :
They can both learn all of those moves, and I might get rid of one of the moves for extrasensory with raikou. My raikou is timid, so I can't change the nature, but with jolteon I know i'd most rater go with modest.
Timid raikou has a base speed of 126.5 speed (don't know if it's rounded up or down), and modest jolteon has 130 base speed. So jolteon is faster, but 126.5 speed is already enough to outspeed pretty much anything. (before EVs).
Timid raikou has 115 base sp.atk, and modest jolteon has 121 base sp. atk. So modest jolteon is faster and does more damage, but Raikou has more bulk.
90 HP vs 65 HP
75 D vs 60 D
100 sp.D vs 95 sp.D
But since is an all-out specs attacker, does that matter much in comparison to the slightly higher speed and sp.atk?
This is for battle spot btw