My best reason (maybe you guys won't think it's a good one) for buying a good quality diamond blade is because I have had a couple problems cutting through material and pushing the material probably harder than i should have only to start stalling the saw and wrecking the drive belts (MK gas saw).
With my good blades I really don't experience that any more. I don't know this for sure, maybe someone will , but I personally think the cheaper blades wobble like they aren't close to balanced
Some of his probably doesn't apply to the hand helds
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