Pros: Price, price, price.
Flexible, online billing.
Easy to set up an account.
Voice quality.
Cons: None.
Summary: I began using OPEX as my long distance carrier some time around 2000/2001. Everything was as advertised: low rates, accurate billing, prompt payment credits, quality calls, easy-to-use calling cards. In late 2006, I let myself get talked into bundling my local, long distance, and Internet into one company. I'd "save" nearly 50%, I was told. I switched. I was an idiot. It took only two billing cycles for me to realize that the long distance portion of my bill had nearly tripled from what I was paying with OPEX. The reason it took me two months to figure this out? The bills were so confusing, I couldn't read them. Without thinking twice about it, I switched back to OPEX. And other than the switching fee the other carrier charged me, the process was as simple and as painless as the first time I switched to OPEX six years ago. I can't be happier to be back.