I was also there easter monday, ~2030 onwards for QF6. Place was probably 1/4 full? everyone was making use of the lounges by then. Tables were empty.
We were also in the lounge that same night, albeit a little earlier than 2030. It was no surprise to me that the lounge was only 1/4 full by the time you arrived, Shan Man. Keep in mind that QF6 is the last QF flight out of SIN and by 2030 most pax for the 2105 QF36 (second last flight of the day) would have been boarding/at the gate/on their way to the gate. We also flew the QF6 back to SYD and it was probably only around 70% full that evening, which would explain the light load in the lounge.
Turning to our experience in the lounge: I cannot sing the praises of the staff enough. We were personally welcomed in by Concierge Shirley Lee, who had found out I was to celebrate my birthday the next day. She looked after every need and even organised a birthday cake and some glasses of, what I believe was the P1/CL Champagne Alongside Faith and Eric and all of the other wait staff, Shirley made sure that the SIN Lounge was the perfect preparation for our trip back.
This was my second time in the lounge and IMHO it is a huge improvement on the old QF/BA setup. I really enjoyed this return visit, especially with the excellent freshly prepared food and extensive buffet selections.
Despite some of the comments/gripes on here, I love the look and decor of the lounge INCLUDING the open ceiling! I think it makes the whole space brighter and more inviting than the old dark wood and carpet. I couldn't care less about the Champagne vs. sparkling wine debate, which I am aware has seen some posters prefer to use the EK lounge instead. Based on my experience in EK lounges throughout their network, the food offerings you find there are probably comparable to stuff that ends up in the bins at Rockpool. I'll go for great food, coughtails and tap beer over one or two French Champagnes any day.
As far as I'm concerned, the only piece missing in QF's SIN puzzle is now the hard product on the aircraft. We were in Y+ and lucky enough to have a refurbed 744 on the way back (they've done a cracking job on those), but unfortunately that type is not long for this route! I really hope that management are clever enough to send the first refurbed 330s to SIN, as I believe this would give QF a super-competitive product from end to end. Shame that there appears to be no intention to include Y+ as part of that program. It really is an excellent product for flights of this length!