We only stayed in the Sunway for two nights as a part of our 14 day travels through Cambodia. If you are visiting the city, or have to get to the airport the location is from advantage.
We were extremly lucky because it was the Water Festival when we stayed in Phnom Penh so we watched a bit from the Balcony and then went for it, we walked to the River and watched the beautiful decorated boats going by meanwhile having dinner in the Titanic Restaurant (very good dinner, I recommend this Restaurant). Make sure you request a room with a Balcony if you stay in the Sunway Hotel. Check In/Out was easy and quick, the personel friendly. The Rooms are very dated and the whole hotel has a damp smell to it. The rooms are functional but I would only use this hotel again if there is no other one availble. The safe in our room and in our daughters room was not functional though we had to call Reception up 3 times. The evening dinner is OK, nothing special really, lots of choice on the menu but the service was slow. The included breakfast buffet is allright as well but nothing special either.
All in all, the night here was very memorable due to the Water festival and our City Tour to see the Genocide Museum the Silver Pagoda and lots more. The City is really worth a visit, especially at Water Festival time.

We had just one night to spend in Phnom Penh, and we chose the Sunway because of the chain's reputation and because of it's location right across from Wat Penh. We got a "Deluxe double room with balcony". My impression is that the Sunway hotels position themselves as "business hotels." This was the most expensive room of our 17 nights in IndoChina, so we also compared it to the other places we stayed. By both of these standards, this Sunway falls somewhat short. One robe, no slippers, weak air conditioning. Be assured -- this was not a hell-hole or a "vacation disaster" -- just not quite up to snuff.
As for location, you are across from one of Phnom Penh's significant tourist attractions (and the U.S. Embassy, should you need their services), but about a 25-minute walk from the other attractions (it's worth bargaining with the cyclo drivers -- taxicabs are hard to find in town).

This hotel is reasonably conveniently situated for airport transfer. It is close to the American Embassy, so perhaps attracts a clientel who can afford to pay a bit more. It is quite expensive for Cambodia - food and drinks especially. Rooms very well insulated (no noise) and comfortable. Staff friendly, but orders can take some time to materialise so be patient. I would probably stay there again.

Rooms for business meetings too expensive, but they will let you use the bar area for free during the day time!

Here for 3 nights. Check in good and rooms of a good standard and we were lucky enough to have a very nice terrace balcony overlooking the American Embassy opposite.

This hotel does cater for business people and the breakfast room was full of UN personnel and other suits. Breakfast was of a reasonable standard, although you were often pushed to get a refill of your tea.

Our rooms were not cleaned until mid afternoon both days which we were very cross about as that was when we had spare time and were more likely to be in them. The biggest problem with this hotel is the lack of a swimming pool and given the heat and dust of the city, should really be a must for any decent standard hotel. There was not even as the previous reviewer said a garden with easy chairs to sit in.

We did enjoy the afternoon tea and coffee in the bar, however, where the staff were charming, but the snack meals we had in there were well over-priced even by normal hotel price standards.

On a positive note, I sustained a bite and the hotel couldn't do enough for me. They even took me to their own hotel nurse who looked after the staff to clean me up and then organised taxis etc.

If I returned to the city, I would definetely not come back here mainly because I would want a pool.