Welcome to the Pika boards you guys :D
As far as the thunder jolt goes... based on my own experience, approaching with a running full jump thunder jolt is very good only if your opponent does not attack through it. If his natural reaction is to shield, then this is golden. You can just go for a free grab as he blocks your thunderjolt, or you can Usmash/Nair/Dtilt/Ftilt/anything since the thunderjolt can shield stab pretty often. Sometimes the jolt just catches their foot or hits them at just the right angle to shield stab.
You only wanna approach like this if there's a decent amount of distance between you and your opponent. If you go over your opponent, he can punish you.
Even if your opponent likes to attack through it though, what I like to do is do my running full jump thunderjolt, but immediately hold backwards as soon as I press B so that I don't drift forward as far. When he attacks my jolt, I'm out of range of his attack, and since you can move immediately after you touch the floor again, you can punish his attack depending on which move he did.
I still do this approach pretty often, ESPECIALLY if they don't attack through it (I've noticed a lot of Falcon players opt to shield which is awesome, along with some Peach players and a lot of mid-lower tier characters like pi(ka)chu, Mewtwo, Kirby, etc. It really depends on how the person you're playing reacts to it).
Unfortunately Pikachu doesn't have the awesome non-existent ending lag on his up-b that Pichu has. Pichu can jump so he's BARELY off the ground, up-b horizontally, and after it ends he'll immediately fall on the ground and only have his regular landing as if he were to just jump and do nothing. So awesome lol. Pikachu unfortunately still has ending lag after landing with his up-b, so he can't do the same thing. Well, he can, but it's slow so pretty much useless.
Yup Pikachu's awesome
ika:
