I use the GPS 700 by Wikango alert for several months and I am fully satisfied. The updates are regular and above all FREE! The only downside and the same as for all market warning systems, they are a little less "precise" from the mandatory update to keep them in the law.
The system is simple as I wanted, deactivated, and visual voice warning: one is blue at the right speed during alerts, red is going too fast, there is no simpler.