Hi! I use Smile because it's a little faster and significantly more reliable than the others. Most of my business and personal communication abroad happens via video Skype. Voda and Airtel are sometimes fast enough, but often aren't especially during peak times. I hate having to tell clients that my connection isn't good enough for a scheduled call.

For an idea of what I'm talking about, here's 70 second pings to google.com from an especially frustrating morning in January on Vodacom TZ: http://i.imgur.com/5urJcd7.png. This isn't typical but happens often enough to be a problem.

With Smile I'm paying rates comparable to 4G service in the US, e.g. TMobile[1]. The service isn't nearly as fast (peak I've seen is ~3.5 Megabytes/sec download) but the reliability makes it worth it. I suspect I'm paying as much for lower contention ratios on the towers as for "4G" infrastructure, but the end result is the same.

[1] (http://www.t-mobile.com/cell-phone-plans/mobile-internet.htm...)