Both fruits are delicious and different enough. Someone said Maha Chanok (rainbow mango i think it translates) is naturally (seedling) a little bit dwarfish, haven't had this confirmed yet.
And both should be able to produce polyembryonic seeds so you should be able to get a nucellar clone so you don't have to spend heaps of money on a grafted tree. If the seed contents looks like a jigsawpuzzel it's probobly a polyembryonic seed. ( polyembryonic, more the one embryo).
The cedar bay mango is amazing too, some call it Rubau long, it's a green skin long mango with orange flesh.