The car rental and related insurance fees were fully paid on the Zuzuche website. However, at the local store, I was required to pay an additional 100 AUD deposit...

It's okay

Excess human involvement. The process could be significantly more electronic or simplified. They had to shuffle through keys thrown in a draw for 5-10 minutes before discovering they didn't have the car model ordered so they provided a suitable but very different alternative.

The experience of renting through a rental broker and not directly from a rental company was a little uncomfortable at first (is this transaction legitimate/am I getting ripped off) but in the end the cost saving was worth the third party being involved in the process.

Just another big company with scant regard for customers.

I was pleasantly surprised with both the price and the service.

Like: Vehicle was in good condition ..