With a fire, you're carrying a major fire to the scene, where fuel tanks are very likely to burst. A water landing can only help.
I can't agree that a water landing with a fire is preferable. Of course, no landing with fire is good, and you gotta do what you gotta do, but... considering occupant safety as the primary objective, a water landing will introduce more hazards. If there is a choice between water and decent land for an on fire crash landing, I'd take the land. My reasons: You have a better chance of maintaining control of an intact aircraft to the stop on land, than on water, there is no risk of drowning, if it's been a fuel fed fire, the fuel will spread the fire over a larger area on water than land, and people can't run away from it in the water, it'll be easier for emergency services to reach you on land, a person's injuries will be more likely to become infected in the water, than on land.
I have more experience with this that I would like to have had.