Beautiful clock with poor GPS accuracy

A visually and otherwise beautiful clock - Too bad the GPS function of all criticism scoffs.
The clock is beautiful and I got used quickly to the well thought out features. Although it is very stüört ​​me when you have to be in power forever and data of the clock can not save on your own computer and evaluate.

But - the first I have returned because GPS error in the range of up to 10% at 10 km altitude error of more than 100% appeared to me incredible. I then bought the same clock directly a second time to experience unfortunately without significant improvements. The measurement error persisted. The line was often offset by 100m in open areas displayed the signal often lost - completely wrong paths were shown on the maps and the accuracy of repeated measurements of the same routes were not in a GPS worthy area (beleibe not in the range of 2- 3%).
My conclusion - because other GPS devices much more precise measure (eg iPhone with "professional" app) - I'll get my first GPS clock can purchase only if any on the market this accuracy achieved (ie considerably less than 1% error).
Imagine an ambitious runner, the 10.1 km to 10 km away and the corresponding -richtige - be sold to time!