The Cree branded CR6 has a 5 year warranty compared to the EcoSmart branded version ECO-575 which has a 3 year warranty. The difference in pricing may be more important in this example.

There are many other differences inherent in LED lighting even if various brands use LED chips from the same source such as
1. LED emitter efficiency.
2. Utilization of remote phosphors.
3. Using a mix of different color LED emitters.
4. Power supply components.

Sometimes it is difficult to determine if a seller is simply padding the bottom line by just looking at the box.

Thanks Davidtay - it is hard to know if the packaging is the only difference but sounds like there could be other subtle changes.