What's the difference between Chem C1000, C2000 and C3000?

They are a tiered ladder from the same manufacturer. The C1000 is the beginner kit (~125 experiments, ages 10+), the C2000 is intermediate (~250 experiments) and the C3000 is the advanced flagship with the most reagents, glassware and a burner. Each step up adds more reactive chemicals and more rigorous experiment design.