Hi Bonova

We tracked a few riders at Amageza last year using various apps.
The best by a long way was the iPhone App used by Kamanya. It updated regularly and predictably when in range. When it went out of range it cached and dumped the cache when it got back in range. It worked well, and I gather did not use that much data.
For the Android devices, we used Greenalp (
http://www.greenalp.com/RealTimeTracker/)
It worked fairly well. Setup required authorization from both parties, but that is not such a bad idea. Performance was OK, but not as good as the Apple app. Updates were a bit erratic at times, and although it cached when out of range the cache dump was not as slick. It is however free for tracking up to five devices.
The best coverage was from the deLorme inReach satellite tracker. Updates are sent only every 10 minutes, but it is satellite based and has true global coverage. The device itself costs around R3000, and requires a data plan subscription which is not exactly cheap. It worked exactly as advertised, and Amageza plans to use one of these for each rider this year.
Buy one, subscribe, and ask Alex for a discount on your Amageza entry....