Replying on this very old thread with my experiences.
I also really like the Toggle service while it works. With the new abroad data plans and the US launched it is even more attractive than before.

Everything worked for over one week, but mid second week, my data stopped working. Turned out despite an active data package, it suddenly took data charges from my credits instead of the package, until my credits were zero. I didn't want to top up again because the mistake prevailed. Two days later it started working again, however it seemed to charge approx 10x the data used so my package went down very quickly.

Customer Care is very friendly, however I keep getting told since 5 days now that the issue is under investigation, as well as the billing, and no refund happened yet. Now my trip is over, and I had to buy another sim card for the end of my trip...