Mark wrote a review of Mercury Wheels X1 Carbon Enduro Boost Wheelset - 27.5in on February 12, 2020
Familiarity: I've put it through the wringer
Purchased a set of these wheels at the beginning of 2019. After about 6 months of riding, I broke my first spoke. I am currently on my 5th failed spoke on the rear wheel alone. I ride a lot (and don't enjoy crashing, so I tend to be on the conservative end of the spectrum), and have a garage full of bikes; this is my first experience (seriously) with repeated spoke failures on any wheel I have owned.
On a positive note, my wheel was never more than 3-4 mm out of true even after limping back to the trail-head or home with 1-2 broken spokes, so the carbon lay-up is absolutely bomb-proof in my experience.
I contacted Mercury customer support and they offered to address my problem with a factory rebuild of my rim, which is unbelievable customer service! I'm guessing from other reviews that they went through a bad batch of spokes at exactly the wrong time for me. The rebuild looks and rides great, and I now have a go-to wheel company when I need the next set. I can't say enough about the value of a company that stands behind its products like Mercury does!