My impression was that the shower setup was more modern and in better condition in the garden lounge than in the original business lounge (excepting that there was no toilet, but that could be a plus). The original business lounge showers were pretty good still, however, in my opinion (I went to the showers next to the quiet room area).

I would add, however, that the QR Lounge in Changi had the best shower setup of all! Down to sensor operated doors.

In comparison, however, I think of the Air Canada Maple Leaf Lounge showers in Toronto (international lounge), which are much more roomy but fewer of them, and the ANA Business Lounge showers in Haneda, which are very well kitted out but sometimes have a long wait. Anyhow, QR's showers in all 3 places I've tried them have been quite good.