I've run Cardarine from 3 different labs, and to be honest, I couldn't tell the difference between the 3. There was a notable change in my cardio with all 3 (at my age I notice quite easily when my cardio improves), but i couldn't say that any of the labs was better than the others.
If you find a good lab and are happy with their products (and service), I would go with them.
*** Also, being pre-diabetic, I was testing my blood sugar and noticed slight drops in my readings - however I was using a home glucometer, so take that for what its worth. Berberine has given me more dramatic results in that area.