As a material, Mango is often confused with Koa. This is both on a physical level - they look pretty similar - and tonally too. It's true, they are not that different. Both are dark hardwoods with bright streaks, curls, and ribbons running through their grain. Mango stands out for the colour of these streaks, which can be a bright orange or white in colour. Mango can also be spalted, i.e., having beautiful blackish patterning often found in dead trees.
So why should you buy a Mango uke? Well, Mango has a wide tonal range. It is strongest in the bass and midrange and like a sweeter version of Koa. Warm, rich, and crisp. Definitely not bright, but not super mellow either. For the sound alone, it is definitely worth having a play.