SATS Premier Lounge T3 is relatively smaller to its T2 counterpart but the lack of size doesn't equate to the lack of food options and quality, believe me. Let me take you around the lounge:
The lounge has an open ceiling which actually gives you a better view of the busy airport and you can hear all the activities happening too. It may not be as conducive to working so if you're looking to have some peace and quiet, make sure to bring along a noise-cancelling headset with you. I personally didn't mind though and I can imagine how pretty the view may be in the morning where you can see all the planes landing and taking off.
As mentioned earlier, the lounge is relatively smaller so there's really no where else to go except for the dining area and the couches. Similar to all SATS Premier Lounges though, they offer free wifi and the bathroom has a shower facility which is perfect for passengers with long layovers. I normally don't use this anymore as I would rather shower at the comforts of my home. :)
Check out SATS Premier Lounge at the Departure Transit Hall (Level 3) of Changi Airport Terminal 3.