I can confirm Bulgaria works. When I landed, it was taking forever so I did a manual scan and forced it onto MTEL and got LTE. After I had a minute, I set it back to auto and it swapped over to A1 BG at 2G for a few minutes, and then found what seems to be a good spot on Telenor BG (LTE).
Wiki has been updated.

Speeds on 1+ have been around .25 up and down - absolutely usable as long as you download google maps offline, and avoid video streaming. For email, facebook, and general web it works - slightly slow but nothing painful. This is my first trip outside of North America since moving to Tmobile - so far very satisfied.