US Data Rates seemed rubbish
I've just got back from a trip to the US travelling around New York city and then upstate. I used a UK 3 SIM with the "Feel at Home" package which used T-Mobile for roaming. And it was shocking. In New York City I was getting a full 5-bar signal with 4G but it often wasn't fast enough to load google maps. Even getting enough data to call a cab on Uber was a few minutes wait. Upstate things were a bit different. It was often 3G rather than 4 (and occasionally Edge) but at least there was enough bandwidth to get actually things done. But in and around the city (Harlem, Central Park, Upper East Side, Lower Manhatten) data rates were shocking to none-existent. I actually gave up on using mobile data and was just relying on "borrowing" wifi from nearby stores and cafes.