Need Reliable IAX Providers

Hi,

I'm looking for reliable IAX providers for a trunk out of my switchvox. Unfortunatley the ones I tried out so far are not very reliable in terms of availability or sound quality. The thing is I'm tired of trying out various providers by opening accounts, depositing credit and then realising its the same story again. My main usage will be International Outbound to UK, US, AUS (5%), India(40%), Singapore(20%), Hungary(10%), UAE(5%), Oman(20%). Currently I'm trying VoxGate & RapidVox - havto say their quality sucks!

Can someone recommend me decent IAX Providers (like the SIP Providers Pennytel, CallCentric, Voipwise-its does work) that is reliable in terms of -
1) Availability
2) Quality
3) Good Rates to the above countries

Regards
Renjith