Tang tastes good and I have seen it only in orange flavour, Mango I doubt whether available. Previously it was available in Gulf and South east asian countries but now I see in Indian stores too.
Tastewise, it tastes like real fresh orange juice, but make sure you consume it before the expiry dates. Easy to make(unlike rasna), and tastes great. For regular consumption better to go for fresh orange juices.
I like it a lot.