We tried to book the Cathay deal the day it came out and the spots were already full! We did a search on www.zuji.com and than compared prices with the individual airlines' sites. We ended up booking with British Airways for a trip over Easter. Taxes and other charges amount to about $2000HK.
Oasis seems to be about $5800 return and Air New Zealand ( from Kayak ) Bout $5500. I am surprised that BA is only $2000 unless that is a one-way quote.