Ok, a lot of the stuff here you guys are pure speculation. I have played both(yeah, I am playing Jap SS now) and I think pokethlon is better. Only I wish I knew Japanese so i could enjoy it more.....
I prefer the Pokethlon to contests(since I don't have much time to plant berries).
Everybody, when you get your HG/SS or both, play the Pokethlon. Its fun, I think I'll give a summary of some of the minigames(my opinion BTW).
Bounce Field
This is your first event if choose Jump category(5th and probably easiest category). I liked this one a lot. Especially when I fired Pidgeotto into the Xatu light for 5 points, followed by it by landing and bouncing the second time BY ITSELF and getting 1 or 2 more lights. I LOL'd when it landed on Flaafy and Quilava, making them all dizzy(this team won ALL 3 minigames for me in Jump 5 minutes ago, so please try it out if you can(completely off-topic)).
Catch Saucer(or whatever you call it)
This HAS to be one of the craziest minigames(beaten only by the soccer one). It was really funny watching Pidgeotto push Magikarp off as Flaafy caught the saucer. Basically, what I do to win easily is to get 2 Pokemon to stand in the front(catching saucers), while getting a third to push Pokemon off the place. This way, I get a LOT of 1-pointers and 2-pointers while reducing the others chances of getting anything.
Dash Hurdles
If you have a quick hand, you'll enjoy this. There are 3 stages of boosts, the first being none(at the start when you start, it is signified by a few white puffs coming out at the start), the second is signified by grey lines surrounding you and the third is known as L33T SUPA H4X0R(my own creation) signified by yellow lines.
Completely Off-Topic: I have beat the Jump category thrice, but I haven't got any medals for my Pokemon. How do I get them? Also how do I make ApriShakes(I have the ApriShaker)?