On a tour of Thailand, Laos and Cambodia, I stayed in The Diamond Hotel in Phnom-Penh for two nights. The single room was rather small and so was the bathroom and the space in the cupboard was limited, so I had to leave most of my clothes is my suitcase. But the rooms was clean and the breakfast excellent. The Central Market is just around the corner, but the hotel isn't very close to the rest of the interesting parts of Phnom-Penh and Monivong Blvd is a very busy road and you can just smell the pollution when stepping out of the hotel. But that's the same everywere in the city. The part of the city around the river were all the restaurants, pubs and nightlife can be found, is more than a thirty minute walk and in the tropical heat where you are completely sweating after just five minutes of exercise, you can better take a (motor)taxi, although negociating for a good price instead of a rip-off, will take up some time. If you don't want to travel, the only alternative is to go for the biggest chicken killer (KFC) across the road from the hotel and eat there. But overall, if you are only staying in Phnom-Penh for a couple of days and don't want to pay much for a decent and clean hotel, the Diamond can be recommended.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC