It's billed as one of the world's great new museums and Sydney's biggest cultural project since the Opera House, but its detractors have dubbed it the Milk Crate - a billion-dollar folly built in a flood zone.
Powerhouse Parramatta finally opens in November with five exhibitions and a sold-out program for 20,000 visitors across its launch weekend.
"I think once people get in there with their phones and their Instagram accounts, they're going to be sending messages to the world and all of Sydney that there's a new house in town," Powerhouse Trust chair David Borger told AAP.
The first state cultural institution for western Sydney, Borger hopes the $915 million museum - the price tag for construction includes a collection storage facility at Castle Hill - will come to be regarded as the Opera House of the city's west.
Yet it faces an extraordinary situation ahead of opening, with chief executive Lisa Havilah standing aside as allegations regarding governance and procurement are investigated.
A formal misconduct investigation is under way into the executive following a whistleblower complaint and initial probe, although the precise allegations have not been disclosed.
Spending under Havilah's leadership included generous "artistic associate" appointments and items such as a documentary on the building of the institution, costing at least $1.7 million.
NSW Government Architect Abbie Galvin has stepped in as interim chief executive and says Powerhouse Parramatta feels like an institution that has been under attack.
She sees herself as a caretaker helping steer the ship while the misconduct investigation is completed.
"Once that's complete, they might return, and I would certainly hope that that would be the case and if they don't, then waiting (to find) somebody new," she said.
Borger maintains the Powerhouse board acted appropriately and while he won't comment on the allegations, he acknowledges the situation is challenging for staff.
"Whilst it's been really tough, we're standing by them and we're going to open this thing, and I think it will be something we're all going to be proud of," he said.
Five inaugural exhibitions will showcase more than 3000 objects, with more than 1600 from the Powerhouse collection.
The shows include a ticketed aerospace exhibition Task Eternal, which costs $30 for adults.
Entry is free for four shows including The Dark, an imaginative exhibition put together by figures from Sydney's theatre world.
The Mall explores the evolution of shopping malls, with items such as Levi's 501 jeans worn by Apple co-founder Steve Jobs.
There's also a First Nations-led exhibition exploring NSW water systems, and a display of five works by British artist Es Devlin, who is exhibiting in Australia for the first time.
Heritage consultant and former Powerhouse Museum trustee Kylie Winkworth, one of the project's most trenchant critics, describes the Parramatta institution as a cultural tragedy for Sydney.
"I think people are going to be very shocked when it opens," Winkworth told AAP.
"It should come with a product disclosure warning because it's not the Powerhouse Museum. It's not a museum."
She argues the Parramatta project has little relevance to the Powerhouse's valuable collection and cites significant items formerly on show at the Powerhouse Museum in Ultimo, which is undergoing major renovations.
They include an operational 1793 Boulton & Watt steam engine, which represents the beginning of the Industrial Revolution, and a pioneering flying boat, the Catalina Frigate Bird II.
Winkworth's concerns include the care of more than 500,000 significant objects in the Powerhouse collection, and whether the Parramatta site will fulfil the educational purpose of a museum.
Borger argues Parramatta and Ultimo together will mean more space to show the collection.
"Obviously I think we are still a museum, but equally I think museums are changing," he said.
The NSW government has projected two million visitors in the museum's first year but Galvin expects the institution might see one million to 1.5 million people during that time.
Powerhouse Parramatta opens on November 7.