I only ever bought some things that they have different. For instance
CS- I have their
Fall Festival Palette
All Neutral Palette
Smoky Palette (This one have more colors and brighter ones than BH)
Blush Palette (can get at BH)
Eclipse Palette
22 Brush Set
BHC-
Bh Party Girl
28 Color Neutral Palette
28 Color Smoky Palette
88 Color Matte Palette
88 Color Shimmer Palette
I say all that to say this, I would go with what offers the better deal if its something they both have, or Wait for a sale to buy from either one, I believe that makes it so worth it. I personally think they are the same quality. I got all the CS stuff during black friday sale, they were 50% off. Only other thing I can say is a major difference is I like the color choices of CS hot pots. And Ive read on forums that these two companies are developing their own formulas, but I dont see it. Like I said I would go with the better deal if its not something exclusive to that company
Hope I made sense.. LOL