I definitely prefer the manip where he's yellow.
Given his backstory and his...appearance as Max Dillion, he doesn't seem like a very serious villain, until the end where he likely lashes out at Spidey.
That's how I've always seen Electro, something of an idiot who was given incredibly powerful abilities and he uses them to rob banks and such.
(Let's not forget, he originally got his powers while working on a power line during a lightning storm)
Which is really why I liked his goofy yellow costume. It fits the character.