I have C80 Comfort Black/Orange.
It was too damned low by far.
The uppermost extension was no where near the stated amount. I sent pictures to Nitro Concepts and they sent me a new Gas Lift. Which was not any better. I ordered a 9" gas lift from ebay and fitted it, and now I'm happy. Turns out the extra height is particularly useful playing Elite Dangerous in VR. I can get right up above the HOTAS and sit very comfortably. I can almost mimic the ED pilot position in VR just using my regular desk.
The chair itself is comfortable (now it's at a decent height), though it does get me a bit warm at times. At the price, I can't complain too much, I suspect the chairs that cost 3 or 4 times more are subject to some brand inflation.