Yes, it worked fine under GSM with the current (at the time) Solana CM10.1 ROMs I tried. Data, voice, & txt. WIND and TIM sims. Italy, 2 weeks.
About getting it unlocked...I had the phone under Verizon Wireless here in the USA. I called them, got their International support people, told them I wanted the phone unlocked for use in Italy. They said, "Sure, use this code." It was free and it unlocked the phone for international use. I have heard that it would not help with non-Verizon use in the USA - that you would need to replace the radio code with the Chinese version in order to do that, PLUS still you would need a valid unlock code.
I have also heard that buying an unlock code for this phone is not always going to work. I have no information on that.
With Verizon, every 4 months of regular contract payments entitles the customer to one unlock code from Verizon, which will work with that one phone. If you want to use the phone in the USA on TMobile or ATT, you will also need to replace the radio code, which will keep you from being able to use it on Verizon as a CDMA 3G phone.