BES875 is the newer and upgraded version of the BES870
Edit: Seems the only difference between the BES875 and BES870 is the inclusion of the thermometer milk jug
The BES870 was popular at
$579 https://www.ozbargain.com.au/node/532589
$579 https://www.ozbargain.com.au/node/532093
BES880 is cheaper than previous deal at Costco
$1099 https://www.ozbargain.com.au/node/531416
Users have suggested that Harvey Norman is willing to match these prices starting tomorrow.
Based on a quick google:
Coffee Machine appears to be the same.