>>21768319I got X digitally and Y physically. Digital was great. I could download it at midnight, since my retailer wasn't doing a midnight release. It did take forever to download, though. Over an hour, I think. The only bonus to having a cartridge is that you can play it on another 3DS with ease.
I prefer digital. It's not a big hassle to transfer info to another SD card if you run out of room or if you get a new 3DS and want to transfer everything.
This time around, I'm going physical, though, but that's because I can get it from my retailer at midnight. And my new internet connection is very slow. I would estimate 2-3 hours download time. Having that physical cartridge and box is just a bonus, personally.