If you want an Electric type, I would actually use either Electivire or Jolteon. But between these three, Pichu takes the least time to train. However, I think Ampharos (evolution of Mareep) is the best. Note also that I find Pikachu better than Raichu. However, it really depends on what role you want your Electric type to play. Ampharos has a lot of power, but it should only be used as a tank or supporter, not a sweeper. Pikachu is a glass Cannon, use it only if you don't need an Electric type for protection against a main weakness for your team. Luxray is a good wall-breaker, but it shouldn't be used as the usually special Electric sweeper.