I am on my 3rd unit because their right button breaks after about a year of use. There are a few threads about it on Reddit and elsewhere. It's such a great mouse otherwise.
You may want to consider Evoluent mice. They’re a bit more expensive, but I have mine for 5 years and it works just fine. As a bonus, they have a true middle button, which is just marvelous.
I like the design, but I had similar problems with the hardware. It sucks paying a premium for a poor product. I've had no issues with thee Kinesis DXT Mouse 3. They have a traditional vertical mouse too. Consider these when your current Logitech breaks.
