T-Mobile limits you to 128/256kbps in international roaming. That worked great when it was introduced but nowadays I find that most apps are barely functional at 128kbps. While roaming, I want at least my messaging, mapping and email apps to work and everything else can wait till on WiFi. Even FB messenger and Google maps struggle at that.

Completely agree. I used Sprint's 128kbps roaming and it's better than nothing, but so many basic things just won't load. iMessage and Google Maps were decent (particularly if you download the map for offline).

What doesn't get mentioned enough is that 128/256kbps roaming absolutely kills your battery because the phone's radio has to stay on so much longer.