Econobox.

Drive it like a lunatic (which I strongly advocate), and it drinks gas like you'd expect.  Acceleration never comes for free.  It can't.  To first order acceleration is proportional to power, which is – again to first order – proportional to fuel burn rate.  But once this object is up to speed, it's just a matter of keeping up with friction, the mechanical and aerodynamic losses inherent in anything barreling down the road.  Minimizing those losses is where engineering comes in.  And some very good engineering goes into modern cars.

On this weekend's run over to Florida, it averaged 30.4mpg on I-10.  On an empty stretch of 55mph road where I was keeping things dialed back to a mere 65mph, this jumped to 34mph.  Playing around on backroads closer to home it's getting more like 15mpg, but that's just for having fun.
BTW, some guys from Ford were able to pull off 48.5mpg.  That was on a closed track and they weren't having to deal with RVs clogging traffic.
For all of that, it still has punch.  Just... not in overdrive.  Downshift and take the tach up above 3k, and it has way more snap than its early 70's counterpart.  (Believe me, I've wrung out both.  Though my brothers never saw that.)  Of course, then it's drinking gas like it's 28 cents a gallon all over again, as physics dictates that it must.  No free lunches.
The bottom line is that cars like this give options.  Cruise for cheap, or accelerate out of some idiot's way for the price of a tad more fuel.  (Cheaper than a new fender.)  Or just accelerate for the hell of it.  Which I strongly advocate.
I do love this 21st century engineering.