From what I've heard the 3DS sounds a lot nicer than the PS Vita, since I'm one of the ten people that owns one of those. There's a digital version of almost every game, but all of the games are massive. Wouldn't be a problem if you could just use memory stick duos like the PSP did, but Sony makes it so you have to have their special memory card which are ridiculously expensive in comparison to how much storage they provide compared to something like an SD card.
I'll probably be getting a 3DS with the release of Sun/Moon, unless I buy one earlier to play Alpha Sapphire.