I have use Cebu Pacific and on my trip out from Melbourne the flight was delayed 7 hours.
They gave a voucher for a free ticket so I asked the girl at the ticket counter " Is his a free ticket anywhere?" and she said she thought it was. I was doubtful....
Used the voucher on my return trip and only paid A$ 70 in taxes
My flights were not very full so you could stretch out BUT the seats dont have much padding so my strategy if I fly with them again would be take a pillow and stock up on snacks, sandwiches etc because the food on offer is not that exciting.
For value for money great I think my outward trip from Melbourne was A$320