true, with tmobile you really dont need a global sim card. my kids where here for a week using tmobile, if your just using data for facebook, whatsapp chatting, checking e mails, texts ect, its fine. it 2 g speed but more like 250 k speed.
only problem they had was their iphones kept jumping carriers here, from claro, to movistar to tigo and sometimes would have to reset the phones to get it to connect.