Travel in Nadi by taxi is easy and not expensive, so although it is not near city center or the beach, transportation is not a main concern.
Although the building is a bit old, the room is clean. Just one minor thing, the water is not hot enough for bathroom at midnight while it is normal at the morning.
There is a mall nearby, so it is also easy to access for supermarket and restaurants.
Resorts in Nadi are expensive, so if you look for a hotel with reasonable price but also acceptable service, Mercure shall be a good choice.