Coming from a competitive battler: Pikachu isn't really a viable Pokémon to use. A very fun one, though. The only real use it has in the competitive scene is killing Mandibuzz. Everything else it could potentially do, which isn't much, can be done better by either Raichu or any large number of other Pokémon.

Sad truth. But that didn't stop me. I have a lvl 100 Pikachu. Named it Mighty Mouse.