Grey and white/cream - In bronze this would be a patina, in resin this would probably be a painted finish. I haven't ever done one life-size in grey so its a bit more risky but if I were to do any of my pieces it would be this one.
Dark brown - This is the most traditional looking finish, it's our perception of what bronze should look like, think Rodin etc. In bronze and resin it is done with patination, using chemicals to change the colour of the surface of the bronze or bronze resin. There will be a variation of tone in the low and highlights. I think this piece would look nice in dark brown with a green tint to the bowl. If the bowl is left to fill with water it will naturally do this overtime anyway.
Light brown Bronze Resin - This is standard finish at the moment, the bronze resin is rubbed down to reveal the particles of the bronze powder and then waxed. The dark wax in the lowlights reveal the highlights so show up the texture. Eventually over many years the wax on the surface of the piece will wear away with weather etc but the colour usually stays the same with the dark colour in the lowlights.
The photos below are of the small bronze version so they may look a little different in resin so its just a guide.