Rewards:

When completing a quest, the player gets a certain amount of mango and their guild will also receive some mangoes too. The mangoes earned by a guild each week will be given to their members who've completed Guild Quest(s) in that week according to a formula.
F/T*0.1(F: Guild members who have finished the guild quest; T: Total guild members)

The points can then be exchanged for items.
All mangoes will be cleared as long as players leave the guild.

1000mangoes=100kBone;
1000mangoes=20 Medium Attack/Defensive Spar
1000mangoes=5 FC
20000mangoes=Senior Pet Egg (unbound)
40000 Mangoes=1 Jade Roc Egg (unbound)

If you won prizes in the latest GvG event, here's how to claim your rewards. Submit the required information, including a time when you would like to receive the rewards, to the Mangoes Exchange column on http://service.igg.com/  . The time you choose to receive your rewards should be sometime between 9:00 PM and 12:00 PM EDT (GMT-4) on Monday or Wednesday, or between 1:00 AM and 6:00 AM EDT (GMT-4) on Tuesday or Thursday. Please be online at the time you choose to receive your rewards so that we can give out your rewards.