Also let me add- Also depends what time you arrive. Flagship in T4 is open much earlier than OW 1st and Biz at TBIT- Last month I was delayed and landed around 5am; the lounges at TBIT didnt open until 7 i believe maybe even later, but the Flagship in Term 4 was open at 5.

I really enjoy the Flagship Lounge in Term 4- even though under renovation found the chairs very comfy; the buffet food was really good and nice choice of drinks.

Truth be told, I really don't like the QF 1st class lounge; I stop in to eat at the restaurant but the lounge is too quiet IMO. The showers are really lame, I compare QF to the Flagship and believe shower facility is on par.

Before Departure I always find myself in the Biz lounge & enjoy the juice/smoothie machine

I havent travelled many placed, but IMO the Pier 1st Class Lounge at HKG is still my fav lounge. I will check out the DOHA Biz lounge for the 1st time in a few months, so I will compare, but think the Pier would be hard to beat.