I had used a matrix sim card extensively while I was in Singapore and by the end of the trip I was worrying about the bill and how would expensive would it be. For all that I got a detailed billed history for every call, every text and data consumed, pinned down to every second. I did pay a relatively higher bill for all the calls I had made, but not even once found that the bill was inflated or tampered with. Would say matrix is a good option for international traveling.