Could also with the now fourth Naga not build long-term relationship.

When we first met, fell in love .. looks ... shy displays of affection. After a short time we had perfectly understood us as a team, were another one. But it was unfortunately never more than one yo. We both had our quirks, maybe I overworked it too much.

In short:
With daily use quickly the technique fails.
My 2013er Naga's had quite fast the "double-syndrome" (DKS).
My current (2014er Version) I have for the past 9 months and even with her, I note a gradual decline since the "2" (thumb button) sporadic or even unresponsive.
I hope that this goes through as a warranty, otherwise I see myself compelled, albeit with nostalgia something a competitor the opportunity to give to prove himself.