Board Thread:Dragon City Questions and Answers/@comment-5211094-20130515174922/@comment-3271569-20130516112233

In that case it's better to buy the island upgrade but don't forget you can only place 4 legend habitat's on that island.

The Ultra Breeding Tree is worth the money for:
 * Events
 * If you don't have all dragons yet or want to try to breed an specific dragon you now can breed two combinations add ones.

If you got all dragons than I think your better off with the island.