Before leaving for a trip to Copenhagen, I searched this sub for info on whether my US Cellular-based iPhone would work well on the international plan. It worked flawlessly. Perfect coverage throughout Copenhagen, and it worked as far north as the Louisiana Museum of Art (which is about 45 minutes outside CPH). Just posting this here so others looking for similar info can find it.

Also FYI, the monthly international plan is prorated, something they don't tell you online. So if you add the $100/mo. plan to your phone number and cancel it as soon as you're back, you're only going to pay for the amount of time it was attached to your phone number.

Go forth and explore!