I bought 30 Wall Chaser two of these discs for my Metabo MFE. The discs have worked without complaint. The grooves were milled clean. Of course, one has noticed differences of individual building materials, it was just slow in concrete. Wear I have not yet found. Have been 3x slots for 15 square meter room for a completely new electrical primary care milled.
Conclusion: Good Metabo diamond cutting discs, so 5 stars.