Default [Q] Moto X GSM Unlocked T-Mobile works outside the US?

Hi!

I'm planning to buy a customized Moto X unlocked GSM edition but I'm wondering if it'll work outside the US.
At Moto they don't know as "they haven't tried it". And is confusing as it says on their website that is GSM unlocked but comes with a t-mobile sim card, so it's unlocked to work with t-mobile and at&t only or also open to other compatible GSM networks around the world? Has anyone had the chance to try it?