History, at least from a vintage car collector's point of view, has not been kind to the 1971-1973 Ford Mustangs. The reasons are almost as varied as the option lists for these cars were.
To begin with, values are generally softer on collectible cars built after 1970. 1970 believed to be the last hoorah for muscle cars since beginning in 1971, compression ratios started to drop as car manufacturers began to ramp up to ever stringent government mandated emissions restrictions. High compression, incidentally, meant a "dirty engine"; a more polluting car. For whatever reasons, that drops the value of collector cars.
Secondly, government mandated, 5 mph "safety bumpers" were added to all cars sold in the United States starting in 1973. For 1973 they were added to the front and in 1974 they were added to the rear. While our '71 here was saved from that indignity, since it's lumped in with cars of that safety bumper vintage, it gets another ding in value.

Lastly and far from leastly, our lovely beast gets dinged because of what it ultimately isn't. That being at least a 1964 1/2 - 1966 or 1967-1968 Mustang. Mustang went through three massive styling updates in just seven years and the car morphed from a cute, bug like, diminutive little thing to a bar room brawler complete with an optional "big block" engine. With each update, Mustang moved father and father away from its original and very successful design or mission. Taste being like armpits though, I like these "Big Mustangs". Most Mustang cognoscenti have a much different opinion. Then again, I'm a GM guy at heart so what the heck do I know.

Rubber to the road, this car is typical of performance cars of the era. It looks great and can go from 0-60 mph and do the quarter mile with heretofore unimaginable aplomb. It feels faster than it is too. However, when it came to handling, much is left to be desired. With a propensity to do little more than under steer in corners with anything more than a gentle amount of throttle, driving this "sports car" is quite challenging. You don't drive it as much as plow with it. What's more, visibility is horrible with it's severely raked rear window, louvers and very low sitting position. 

I had passed on buying this car a couple of years ago because of all the above reasons and most importantly, the asking price was, I believed exorbitant. It was nice Corvette money for a Mustang. Sorry but no.

It's said that the two happiest days of a boat owners life at the day they buy the boat and the day they sell it. Same could be said for vintage cars.