GSM phone quality is excellent. Generally the signal strength is better than on iPhone 6+ or Samsung Note 8 that I have in the house. All on the same network. Voice is loud and clear and calls don't fall out. Also in roaming, driving through different countries, switching between networks is instant and call quality excellent also in high speeds on the highway. And driving sometimes I have conversations in roaming over an hour long without being dropped. Always connected with Bluetooth to my car's multimedia system.
VoLTE is supported by my provider (T-Mobile Croatia), but on my phone that option is greyed out. The Rog 2 international version has all LTE bands used by Croatian providers, but I can't use it at the moment. Will check with SIM cards of other 2 providers to make a final conclusion. It's not that important at the moment, as the GSM works perfect, but as everyone else, I would like it to be sorted out in the future.
