Just a quick tip for the 3DS. After setting up your 3DS account, check out the Nintendo store and under the options select the download history tab. Your 3DS may have games purchased from the previous owner or even better it may have the ambassador status and the free games that go along with it.
I got lucky because one of the 3DS consoles I picked up from cowboom had about $30 worth of digital content on it. Another 3DS I picked up from cowboom didn't have anything so it is hit or miss but it's worth checking up on. And if the console does have content to download make sure you don't format the console memory because it will wipe out any purchased content linked to the system.
I was in the same boat as you (sold my vita because of the lack of games that interested me). I'm really glad I picked up a 3DS, so far I am loving the console.
Haha, thanks for posting this. I just logged onto the store on the $50 purple 3DS I got and there was still $20 in the system's wallet.