Pros: Cheap rates
Cons: Terrible, horrible, rude customer service.
Frequent international disconnections.
Summary: After using this service for over 5 years, my phone was suddenly and inexplicably disconnected without any notice. After many frustrating calls to OPEX and the assurance that I would be re-connected (ridiculously enough, it would take them a week!), I was still without service after 2 weeks. I just placed my final call to them to say I wanted to completely discontinue my relationship with the company. The operator said, "oh, you've already been disconnected, so ok."...this the response after years of getting my business??? She never offered an apology or attempted to keep my business. She couldn't have cared less. I will never recommend this company again.