Just a quick update from South Korea, T-MO USA global roaming data working fine on both Androids 5.1.1 and iOS 8.4 on iPhone 5s and 6s ... no issues with Facetime, Talkatone or Facebook uploads at basically 3G speed, but just experience slowdown at slower 2/2.5G speed due to congestions.

iPad Mini's FDFL plan isn't working (as expected & per TOC) but at the Novotel Ambassador here in Seoul, getting blazing turbo internet speed 75MB up/down-loads over hard-wired ethernet in-room.

We're up at the 38th Parallel this morning & doing just fine with SK Telecom coverage on both data & voice - just like coverage along the Eastern coast of SK (all with no extra charges)

Slightly off-topic: voice calls over WiFi & billed at 4 cents per minute worked on the prepaid line (not to be confused with global data roaming for free on lines with postpaid coverage)