It is a legit company, no scam. This is my second time unlocking a phone with them. Unlocked a HTC One V in April 2013 for 15$ and now unlocked a HTC ONE S for 10$ in February 2015. Don't know if the price changes or not based on the oldness of the model, but it's irrelevant.
One thing I didn't like the first time is that I waited a bit longer than the first time, 15 hours compared to 10 minutes. But that's just a detail. What matters is that I got it, the unlock code that is. Would give 5 stars for a more consistent service.