Outside Japan if 3DS struggles hard (both hardware and especially software wise) PS Vita will bomb hard, if 3DS under-performs then PS Vita will disappoint badly. The more 3DS sells the better for PS Vita since it will have more chances to be a success. This is not about consoles wars but portable console gaming ecosystem that it is apparently in a real bad shape. Mainly due to the western media and developers that hate portable consoles, they just can't conceive anything outside smartphone games. 

Loads of parents bought the DS for their kids, then some parents even bought them for themselves. so can Sony capture this Pokemon, Mario type craze for the PS Vita.

maybe... the price is still expensive, and the games are unlike those of the casual DS nature. theres a few games in there like Uncharted and Little Big Planet that might have a shot at doing what the PSP couldnt.

however the big thing this time is Call of Duty. personally i think COD needs to be the game that is advertised with the PS Vita. its then only game i can see with enough weight to rival Mario and Pokemon. maybe people wont buy a PS Vita because of smartphones, but will teenagers and kids get it, maybe... lastly the dual analogue stick is key, this offers people a way to play FPS, or any game properly, unlike smartphones or the 3DS.

Sounds like GTA4 vs MKWii all over again.

There is no doubt in my mind that the 3DS will win by a decent margin. However, the gap will be much smaller than in the 7th gen and I wouldn't be surprised if in the first year or 18 months PSV is ahead launch aligned

I think COD is bigger than GTA tbh. and the other thing is the dual analogue, which lets you play it properly. so imo, i dont know, but this is the best shot Sony have at the handheld market.

Call of Duty is a console game. No way is a handheld port going to sell even close.

Call of Duty was already on both the DS and PSP. Go look how good it sold. And the franchise does not even come close to Mario Kart. Call of Duty had 31 different games made in its name with about 100 million in sales.

Mario Kart had 6 with 80 million in sales.

3+ million per title, or 13+ million per title.

StarFox 64 3D, Kid Icarus and a new Mario game for the 3DS, Nintendo will move some units. I wonder what other game on any handheld that sells like pokemon except Mario/Mario Kart.

Nintendogs and Brain Age (and Animal Corssing).

Vita will win probably, especially they're both at the same price. 3DS looks more like a new DS iteration while the Vita looks like something completly new.