The Marriott rates are outrageous - SGD 320 even during the weekend whilst I could get the Ritz Carlton Millenia for SGD 290 or Four Seasons for 260. Give me a break.
It's not exactly a dump, but the older rooms leave a lot to be desired, Platinum recognition is poor beyond the basics like non-renovated exec floor room. For any other upgrade, even renovated exec floor room (very nice), I always have to argue. Lounge is decent if you can find a seat - it kind of reminds me of LH Business Lounges at FRA with standing room only.
If you can get this via Priceline for about USD 100, it's not too bad. But it's no JW Marriott Bangkok/Jakarta/Hong Kong or even Surabaya.
Having said that, the Hilton isn't that good either.
I prefer the RC, Raffles the Plaza or the Swissotel Stamford but points and possible upgrades drive me to the Marriott every time.