We have had the Garmin fuel sensor for a couple of years. It gives you readings of gallons per hour,miles per gallon and total fuel left,your range based on the amount of fuel you have left and miles traveled. The gallons per hour lets you pick out an efficent rpm/ speed for economy. Nice to have a handle on fuel used/ho you have left as fuel gauges in boats can be pretty inaccurate. I have it going to our 4208. You do have a remember to add fuel to the system everytime you fill up. I think it's pretty reasonable, all things considered.
D.D.