I think the big problems with Mango lies within the characteristic. Mango has virtually nothing manufacturer-specific features. All Mango looks the same, HTC, samsung, LG, Nokia. And that makes us shun away. Why the hell would I buy your phone if everyone else is going have the same features, other than the maps?
The "Tiles", for simplicity, they said, is one of the least-user-friendly features I have seen. Even using terminal is easier than that.