It is nice since it has two thumbsticks but can't use a SD card with an adapter in it like you can with the PSP and the memory cards are expensive and limited :(
Yes you can, you get an SD card adapter that goes in the game cartridge slot, not the memory card slot. I have one in my vita right now and it works perfectly.
I didn't know that O: I thought I had to put up with those shitty little memory cards or the tiny internal storage that comes with the slim ones. That's awesome, almost seems way too easy. Maybe I'll pick one up since I won't need to worry about those awful and expensive memory cards.