A:AnswerSandisk doesn't even list Pixtor on their product page and a quick search on Google and Amazon indicates that Pixtor are just renamed existing products without the tier classification.
A:AnswerYes I've had it in my New Nintendo 3 DS XL and never had any problems with it. It's not technically approved by Nintendo but almost none of the 2party accessories are.
A:AnswerIPhone does not use memory cards because it monopolize buyers to choose from the different built in memory the phone has on its different prizes. The more memory it has the more expensive the iphone becomes. Compared to the phones that uses memory card...at the minimum prize of the basic gigabyte that you buy and even if you add extra memory card for an additional cost, total cost will still run cheaper compored to iPhone.