Just remember that Freedom Pop is VoIP service. Call quality is good if Sprint 4G LTE is available, but unusable for 3G data IMO. I have it on my Samsung Galaxy S3.
Emergency 911 calls use Sprint's mobile service, not VoIP. It assigns a temp non-regional phone number to the call, not your assigned FreedomPop number which can confuse 911 dispatchers. I had to use 911 to update Police to a location of a hit and run vehicle. The non-regional area code didn't match my contact phone no.