How is Google Voice clearer?
The issue with the free conference phone services is that they use telephone numbers in rural areas that, due to FCC regulations, have high per minute wholesale interconnection fees that your phone company (Verizon, AT&T or whoever) has to pay to the rural phone company in Iowa (or whatever rural area the phone number terminates in.) This is how those conferences services are free. They’re getting a kick-back on those per minute fees that small phone company they use charges your phone company. Which is why some cellular or landline companies block those numbers. Google Voice sometimes will charge you a 1¢ per minute fee, even though generally all other US and Canada calls are free with Google Voice.