Since it's a Western developed product, I highly doubt it'll hit overseas before it hits here.
Since there is no online multiplayer, just local wireless multiplayer, I fully endorse the PSP version. You have only have two slots on the DS version, plus downgraded visuals. The PSP will give you as many slots as you can put on a memory stick and I think the visual presentation is a lot slicker.
The only issue I have, is after a lot of battles, you'll realize that some rely too much on chance. It's not really fair if you set off a combo which unknowingly gives the guy attack skulls already lined up. I was playing one around where I set off a pretty innocent combo, and then like 5+ damage skulls dropped. The computer was able to link like, three damage attacks.