Love it or hate it? It's a tough call for many people as it is one of the more bizarre-looking exhibits in the zoo world. If one looks beyond the weird "golden arches" then it is actually a great platypus enclosure.
IMO all of the modern architecture is set off brilliantley by the live plants inside to create the perfect balance. I don't mind a beautiful natural exhibit but exhibits like this that can create something out of the ordinary but still be a great home for it's inhabitants that really catch my fancy.
It is a wonderful-looking structure, just not in a wildlife park though. I get the impression that the designers were not confident that the animals, plants and landscape would be attractive enough and decided to compensate for them by building an eye-catching shelter. IMHO it takes away too much attention from the animals / natural surroundings.
On one website it said that $600,000 was donated by BHP to implement a waterways initiative at Healesville and the platypusary was part of that. That's the best I could find I'm sorry.
It seems my "love it or hate it" description was appropriate, as this exhibit has divided ZooChatters on this forum. There are two platypus exhibits at Healesville, and the second one is a more traditional enclosure that is found indoors.