The fuel totalizer is really great on long trips. I have it linked to
my Garmin 430 for "fuel at arrival" estimates en route. I also like
the "mpg" readout for tuning mixture and headwinds.

I agree. I especially like the feature that shows the number of gallons of
reserve you will have at your destination. Once on a long trip with strong
headwinds (5 hours!), It was very reassuring to know that after adjusting my
cruising altitude, I would have a 20 gallon reserve.