I'm planning a trip to Addis Ababa and Harar in a few months. This will be my second time in Africa (spent 10 days in Senegal this last January). I'm planning on getting a sim card as soon as I land so I can work while I travel. How's the quality of the 3G/4G network there (specially in Addis Ababa)? Is it fast enough for Skype/Magic Jack, etc?