Image quality results from a second lens have been added to the Canon EF 16-35mm f/2.8L III USM Lens page.
Just in case the first set of results weren't convincing for you, the second should be. The two lenses produce nearly identical image quality.
B&H has the new Canon EF 16-35mm f/2.8L III USM Lens in stock.
This lens is also in stock at:
Adorama | Amazon (3rd parties) | Beach Camera | BuyDig.com | Canon Store | eBay | WEX Photographic