I just signed up and started using MyVoipTraffic. I've been using their Premium route for USA and Vietnam so far. The quality is good, as expected. The only problem with them was getting my initial deposit of $100. I used UKash to obtain my initial deposit, which is less expensive then bank transfer and about the same as Western Union but the credit was deposited right away. Also, be aware that after your initial $100 deposit, the minimum deposit increases to $300.
Dellmont (owner of MyVoipTraffic) just started a new brand called
http://www.voippro.com . Their rates are a little lower than MyVoipTraffic but I believe will eventually go up. Has anyone tried them yet?