Bought the RS 126 almost 3 years ago to the day. Was impressed at first - the sound quality and functionality were good although the headset is cumbersome and heavy, overall I was satisfied. We did not use the item heavily, maybe on average once a week and it was never harshly treated. Before it's 3rd birthday the right side stopped producing sound and none of the suggested suspects (batteries, volume, interference, distance, tuning, etc.) were to blame. A system failure. Sennheiser suggested the most cost effective solution was to buy a replacement headset at $60.00 (+tax+shipping).
Not impressed that the unit's life expectancy is only 3 years, especially for something with the Sennheiser name and expected high quality.