Okay i just measured my Vita compared to my 3ds.
the Vita is 2 inches longer, and is half a inch taller. bulk is the same.
I also measured the DS lite and PSP go they are the same size as the 3ds, but the PSP go has the advantage due to its rounded corners , giving it a much smaller size.
When I talk about portability, I am talking about putting it in your pocket, and it not being unobtrusive. The vita is completely obtrusive, that it pulls my shorts down on that side. If you toss it in a bag of course this does not matter, but I think this is why casual gamers, and most of society have moved on to cell phones, you can kill time, with games, and web browsing, while keeping in contact with people via text, or calling/video chat on 1 device.
The vita was a beast of a portable but it is a hog on power. I think Sony only validated this by turning the vita into the Playstation TV, keeping it stationary, and connected to an AC outlet.
I also remembered that the Vita, and PSP both were a pain due to it's analog sticks. the PSP go had the slide out design, and the DS's have a clamshell design making it easier to take it out of your pocket, as well as put it in without fear of damaging the analogs.
