Who offers the best Prepaid calling card service?

Which service provider offers the best-prepaid calling card service?
Compare:
• Minutes - (most minutes / cheapest per/min rate)
• Phones - (most phone choices, best quality)
• Coverage - (national and regional)
• Features (nights and weekends)
• Service - (refill options/locations)

It depends on where you live and what kind of service you need. I found a good long distance call services at www.prepaidcardstore.com They claim to have lowest Domestic and International Phone Rates.