Specs don't mean shit these days, DS kicked PSP in the nuts and Wii raped both 360 and PS3. I vote 3DS by default right now just because I already know what games will be on it for the masses to care about in the long run.
you have disregarded an important fact, PRICE.
Remember that the DS at the time of release was $150 while the PSP was at $250, and the fact that it had the touch gaming gimmick, which took off on the smart phones as the masses loved it, and something the PSP never had. So no matter how high tech the PSP was it was just to expensive.
Come to the present day. The 3DS price is $250 and the4 PSvita has been priced at $250, also the PSVita not only has a multi-touch screen (similar to smart phones) it also has a multi-touch track pad. So given that both machines are the same price, the customer will turn to value, as in which device does more for the same money, and clearly the PSvita does more than the 3DS.
One thing to also factor in, is that portability is no longer an issue, poeple have already accomidated their life style to large devices like the Ipad and other tablets, gone are the days of ultra small phones, and in are the days of smart phones withy 4.3 inche screens.
The world has changed my friend, it's no longer the days of 2004, the hand held market is no longer the same, to disregard the PSvita is just silly, Right now the PSvita has everything in it's favour to really do Nintendo some damage and even has the potential to outsell the 3DS.
Tablets generally sit next to people's beds =P Also, they really need to figure out a good way to protect those screens and maintain portability, that shit is already too big, my PSPs are thin out of the box but after a protective case, it's at least as thick as my DSL and longer which is BS, the Vita will be worse if I have to slap on an actual case to protect it from breaking. It's supposed to be a portable device that I can easily take everywhere, not some giant ass thing I can't put in my pocket when I'm trying to travel light. Also, speaking of gimmicks, what's Vita's gimmick anyways? 3DS has 3D, Vita has....???? You also bring up a good point about these 4.3 inch smart phones, I have an Atrix 4g that's already taking a good amount of my pocket space, how am I suppose to fit a giant ass Vita easily along with my 3DS, my wallet, my keys, my earphones, my goggles(don't ask,) my Blackberry, my micro usb cable, and a set or 2 of other keys? I'm already wearing cargos and I hardly have enough room for what I already have, the size of the Vita is pure ass if I can't just put it in the pocket and go without thinking that it's a burden on the side. We are in the age of a crap ton of stuff we have to carry, this thing is gonna end up like my PSPs and never leave the house which would completely defeat the purpose of me wanting to take it on the road with me while trying to travel light.
The world hasn't changed, we still have to carry too much shit, and people won't bother taking the Vita outside the damn house if it's that big. Their only possible saving grace so far is that they are the same price, which could change very fast as well, oh, and female user base, they need to address that, if the Vita can't cater to females, they'll still be in deep dog shit.