Originally bought because of wrist pain, I've had the kinesis advantage for 16 years, I'm on my third one and I've worn out keys on each one from so much use. Luckily they shipped me new switches for free and allowed me to switch the myself (at my request due to timing). Fantastic service and product. I really do wear them out.
With that said, all three exhibited the sticky modifier problem. I'm used to it but it always made me wonder if the internals were going bad.
In March I preordered https://shop.keyboard.io
I'll be very interested to compare, and if it isn't as good or better, I won't hesitate to order the updated kinesis advantage.