I used a matrix sim card on a recent trip to Scotland and I have to say that i am glad that I did! The last time I had mindlessly used my Delhi number in London and paid some really heavy bills for it.. So this time I was clear I wasn’t going to do that, hence chose Matrix sim cards.. Their calling rates are good in comparison to others, call quality and network both were good too.. And the best was the data plan that I had on my number which was a part of the plan I took.. Awesome!