I had vert star magic Marys on my DH bike. They lasted about the 30 days. Knobs definitely start flapping about towards the end of tire life, however I'd describe it as the side wearing out at the same pace as the middle.
I basically felt like the tire was more thoroughly "used up" at end of life. Minions usually have more side knob left once the middle Ramps are roasted.
If you're the kind of person who runs tires until they're bald, I'd suggest this will be a problem. I'm the opposite. I liked feeling like the tire had nothing left to give at the end, accepted that they wore a bit more quickly, and enjoyed all the sweet sweet grip while it lasted.