In addition to the monthly charges, you'll also be billed for the time it takes to transmit faxes. On average, faxes can take 20 to 60 seconds per page to transmit. The time is dependent on how many graphics appear on an individual page. The per-minute rates for sending faxes to other countries seem to vary between the two companies.

The international sending prices for j2 seem to vary slightly depending on how many minutes are purchased a month. See for yourself here. Compare these prices to those of eFax, which bills in 30-second intervals. On the surface it looks like eFax has the better pricing plan.