Going based on appearance of speed, to me, it didn't look like the hover board went any faster than the skateboard.
I've got the skateboard and one of my daughters has the Lauren costume. To me, it just seems like the Lauren goes faster than my skateboard. Of course it could be optical illusion, it could really be faster, or just in my mind that it is. I really thought the costumes wouldn't increase speed at all, just because they are for looks, not something that would lead us to think of it making us go faster. I kinda don't even like them.
I'm still on the fence as to whether there is a speed difference between the different objects or not. At first I really thought the pogo was faster than just walking. I mean, it honestly LOOKED like it did. And I do think they do aid you 'some.' I'm just not too sure that there really is a difference in speeds between the objects, though. There may be some, but it's very slight. However, even if there is a difference, is it even significant? I highly doubt it is. Like Divelucaya said, what is a second or even fractions of a second going to really do in helping you in the game to get places faster? Not a whole lot.
It's nice that we have them though!
~Vicks