Most all of the relevant points have been made one or more times, but as an owner-from-new of a '72, I thought I'd throw my $.02 in.
The Leno video presents an amazingly comprehensive perspective on the facts of what a Pantera is. If you want to get the essence of the car, watch it one or more times.
A comparison - GT vs Pantera - just doesn't work. 30+ years of technology improvements present too large a difference to ignore/overcome.
In the day, the Pantera was a uniquely positioned supercar in the spectrum of what was available, not really lacking in any area, and superior in many. In terms of value/performance for the $, it was clearly superior. Value proposition is still there today, if that's a niche that you want to enter.
If I had just the GT, I'd be somewhat hard pressed to come up with real reasons to acquire a Pantera. ( Standard conditions of wife and storage space apply. ) Curiosity and lifelong Ford guy are two reasons that might carry the day.
In '72, I was curious and a Ford guy. Thought the Pantera was dynamite, and just had to have one. Flew out of Newark one day, and on the docks were acres of them, in every color. That was the tipping point as far as moving ahead. Surprisingly easy to buy one, as the local L-M dealer had 13 of them, in almost every color. After a test drive I was totally hooked. I had a '68 GT500 at the time, and thought the Pantera was representative of the next leap forward in supercar design. Kept the Shelby - which was my daily driver - and bought the Pantera. Built a garage to hold both, and never looked back.
Having the good fortune of owning both the GT and Pantera , I will never part with either.
Both are unique and timeless, and will instantly attract a crowd wherever you go.
Back in the day, I thoroughly enjoyed exploring the performance envelope of the Pantera. In those situations that presented themselves in standing start; roll-on; and top speed, I was never bested. Also won several autocross championships, and had a blast doing so against a wide variety of competent vehicles in the top street classification.
If you have the itch to do so, I wouldn't hesitate to buy and enjoy one. Just take Leno's advice, and seek out a "Pantera" guy to help you, just as you would look for a "GT guy" to do a PPI if you were buying a used GT.