Don't want to hijack this thread but I have similar situation where in mid January I will be arriving at HKG at 10:30pm, but leaving next day at 8am (KA J). I am just looking somewhere to sleep before next flight out:

1) Try to hang around Plaza Premium lounges overnight (with Priority Pass), and then go to CX J lounges;
2) Use 30K Marriott points to book Marriott SkyCity hotel but it seems a waste of points when all I am trying to do is sleep and nothing else; Even as Marriott Gold I won't be able to take advantage of free breakfast as I have to be at airport at 6am anyway;
3) Try to look at cheap accommodation say Rambler Garden/Oasis (for $370 HKD) as all I care is a few hours sleep, and catch S1/MTR/Tsing-Yi taxi or local bus;
4) Pay to book at Novotel Tung Chung or Regal Airport but they are like $1540HKD which is steep for a few hours sleep;

Which is the best option based on above?