I inherited a Samsung Galaxy S6 from my brother when he upgraded. But I live in Europe, so I needed the phone unlocked. After previous experiences messing with the network provider for months, I decided to go straight to an unlocking service. They sent me an unlock code in about two days, and it worked as soon as I tried it, which wasn't until about a week later because I didn't have time to pick up a foreign SIM card!
Bottom Line: Yes, I would recommend this to a friend