That cruise control is a gas-eater when you leave it on its own. Most of the high-mpg types here cringe at the thought of "3500-4000 rpm seems pretty reasonable for getting back up to speed." If you care about fuel economy, don't let the cruise control accelerate the car, and don't hit your resume switch until you're already at the speed you want. If you hit it a couple
mph below your set speed, the car will still rev an extra 1000 rpm trying to race you back to your set speed (and we have to use the word "race" with this car advisedly to begin with).
As you play around with it, you'll find times when, say, your cruise is set to 65, your tach is sitting at ~1900, you encounter a slight rise, your speed drops to 64, and the car revs to 3500 to try to get you back that 1
mph. Whereas you could use enough foot to raise the revs to 2100 for the same amount of time and recover the 1
mph -- if you even cared; you could just maintain the 1900 revs, do 64 until the terrain itself lets the car return to 65, and never waste a drop of gas.)
The cruise in general will rev you 1000-1500 rpm higher than you need if you're driving manually -- because, driving manually, you don't mind tapping the battery, but the cruise tries not to; it's programmed to conserve as much battery as possible, because unlike you, it can't look up the road and see how long the hill is. If you need battery management on hills, use the cruise; if you need fuel economy, use your foot.
cheers --
doug