I´ve stayed at the Fairmont SIN a few times (and am staying there right now, so if you have any specific questions, feel free to drop me a PM and I´m happy to look into it), and have been pretty pleased overall.

However, your experience will greatly depend on what room category you´re planning to book.

Executive Club rooms are pretty nice: great views, very good (western-style) full breakfast and some hot food and comp. drinks in the evening. Best feature is that all guests staying in a suite get comp. lounge access, too.

regular rooms are ok IMO, but nothing to get excited about, many good options in SIN.

there are some great suites (see my profile for some photos of the Penthouse suite I was lucky enough to be upgraded to during me previous stay), and again the views from floors 20 and higher are pretty amazing.

One major advantage of the Fairmont SIN / the Swissotel Stamford (which are indeed owned by the same company) is the great location.