In my opinion, all rainbow chalices are pretty much the same. They are all just variations on the same coral. You get different combinations/proportions of the same red, blue, green, and orange. The frags you see for sale only look different because they are cut from different parts of a colony. Some parts of my rainbow colonies are incredibly intricate with lots of different colors going on in a small space, while other areas are more bland. Rainbow Crush, Jelly Bean, and Masterpiece are all the same colors just different proportions and patterns based on where they were cut from. There are some rare rainbow colonies out there that incorporate more than just the red, orange, blue, greens and might actually throw in a pink or purple color, but I don't have any of those yet. (like the one from Jordy)
If you have one rainbow, you have them all. (for the most part) And, as pointed out by braves fan, just because its a "rainbow crush" or whatever, doesn't mean you're going to get all the colors you're looking for. Depending on where it was cut from, it might lack certain rainbow patterns/colors.