My experience from Movitel have been a pretty good one.
All you need us to buy a sim card of any of the network and insert it in your mobile phone.
Call rate for Movitel ranges from 3MT/1M to 0.39MT/Min depending on the tariff plan.
The internet of Movitel is pretty good, fast and reliable as it has a wider coverage area than other network as been experienced.
I called home twice, did not check the charge rate but the call was clear and my airtime since then still lasted me for a while.
With bonuses of SMS and Data (MB) depending on how much you recharge on your phone, Movirel have really been a cool experience.