I am a bit of a fan of Schwalbe tyres, especially the Hans Dampf which goes against the grain on here sometimes, i popped on a brand new a Magic Mary for a week in the Alps and have run it since i got home for about 5 good long day rides since then and it looks like it has been in the wars. There were tiny hairline cracks after the first ride along the outer nobbles but to be fair there seemed to be no damage while riding. The nobbles are all slightly damaged with chips out of them.
They are grippier than a grippier thing in gripsville but their longevity is definitely in question at the moment.
These are Trailstar compound so maybe not unexpected. Ill run them for a while longer just to see how they hold up.