Engineers edition won't be out for a few more months.
I sugest you get WBE now and add EE to it later. That way you will hsve the best of both plus you can enjoy WBE and maybe make a layout or two while waiting for EE. With EE by itself you will not be able to make layouts.
World Builder Edition is just that, a version to build layout and develop content in. Engineers Edition will be driver only - no surveyor to build your own layouts.
As SuperFudd mentioned it is not available yet. If you get WBE now you can do everything and more that EE will do once it is released.