Now that US Roaming is live and prices are out I have a suggestion.
The prices are amazing for multi day trips, but when looking at what the options are if you just want to hop over to the US for a day trip Roam Mobility still wins with $4.95 for talk, text and 500MB of data.
So how about a single day pack? It can be considerably more expensive than the "per day" rate of the 10 day packs, and maybe even a little more expensive than Roam because you get to keep your number and have the convenience of not switching SIMs.
I would probably be willing to pay $6.00 or maybe even $7.00 for a single day pass with unlimited talk and text and 250MB of data. Or maybe even drop the text and just data and talk for $5 or so? Most of us can use iMessage/Whatsapp to handle our text needs for a day. It would be a lot better than dropping $8 for just talk or $10 for just data that is valid for 10 days on a 1 day trip.