I'll toss in my experiences. I've been to Singapore many times, these last two recent stays here at the Hilton. Currently, the Hilton is undergoing renovations. They are redoing the outside and you can expect scafolding and construction noise during the day. The hotel is ok - but there are many superior hotels in this city. So, if like me you're staying here for the points, great- but if you want service / etc stay elsewhere.
I'm Gold and so upgraded to Exec floor. I haven't tried it yet - but about 6 weeks ago the exec lounge was closed, under remodel. Got a free drink chit for the lounge downstairs.
Service in the downstairs restaurant today for breakfast was fair to lousy (only option on Sundays; otherwise can use a small scaled down exec breakfast nook, which I did last trip, which was just slightly better in service).
The most annoying factor this trip - and one that almost had me walking next door to the superior Four Seasons (but no points/ miles there) is that after a 19+ hours in the air, traveling from Portland, Oregon, and arriving at midnight, I was told that the water was shut off from midnight to 6am for repairs. So, no shower before bed, which I totally thrive on after a full day in the planes.
So - if you can - I'd certainly stay at the Conrad (which I would, but it's not on my company's list of approved Singapore hotels) if you want to stay at a Hilton property.