Board Thread:Game Discussions/@comment-97.68.161.51-20131207144624/@comment-23870891-20131207194339

The training fields do generate gold faster at level 3 because the amount of time it takes to fill remains the same at all levels, this results in more gold/minute in order to fill in the same amount of time.

In regards to getting monster nests instead, that is a much larger gem sink.

12 Training Feilds * 35 gems + 1 Monster nest * 40 gems = 460 gems.

25 Monster nests * 40 gems = 1000 gems.

For most players, training fields generate more then enough gold to contribute to guild and max 1 boss plus armor a week. If you need to upgrade and epic, sacrifice upgrading some boss armors or let your guild know your contributions will fall short for a while.

Training fields also have the advantage of larger capacity, so if you need to be away from the game for longer you do not lose gold.