Been using telestunt for about 6 months now and can only recommend them, even for calls to Irish mobiles they are cheaper, except at the weekend I think.
Tried Telestunt yesterday for a 2 hour conference call to the USA. No difference in quality, big difference in price. They certainly pass the test. Cheers TirOileain!
Used to be called Budgetcom up to a few months ago (or so). Just checked a spanish mobile number on telestunt and it's the same access code as budgetcom.