We went to USA with my family and friends in June 2017 for 21 days and bought 6 matrix sim cards as it offered unlimited calling within USA and to INDIA with 5GB 4G data.First 7 days in California service was ok but after we left California 95% of the time we were unable to call each other and only data was working. We complained several times to the matrix people in INDIA but they always said that they are working on it, later they stopped answering our calls, so we were left with no choice other than buying new local connection .
I strongly advice not to buy matrix connection.