My recent experience of using Matrix sim cards has been quite the opposite of what I had heard and read. I rented their sim card services for Spain. Since I was only traveling to Spain, I bought their Spanish sim card. Great price to begin with. Got 1GB data with and some 500 minutes of calling to India all in close to some Rs 3100/- I was anyways pretty excited for such low pricing but was glad when I actually used the sim card. No hiccups in the network or any other service. Everything upto mark. Excellent!