Used it to replace the cellular modem I previously had for my public coin telephone which went toast. Now I can get it working again without having to pay for an expensive copper landline, so I can keep it in service. The call quality is strong and clear and has enough power to ring the classic telephone bell ringers.
I would recommend this for someone looking for a decent landline replacement, please note this DOES NOT support fax or modem data. I have not tested the ethernet or Wi-Fi capabilities, but it is working.
I used the Ultra-Mobile (T-Mobile) PAY-GO plan and only costs me $3/mo.