Build and restoration quality of the car is great but "Lucas"-like wiring is an issue. Initially I had a LOT of electrical Gremlins to deal with to get the car plated so I could drive it on open roads. Almost none of the lighting worked properly except the headlights. Then a few small issues needed attention (trunk wouldn't stay open, rough idle from a cracked graphite post in the distributor, fluid changes, a solid cleaning inside & out, paint chip & scrape touch-ups, wet-sanding, buffing, replaced some small missing trim bits, new signal lights all around, new headlights (thanks to Simon in Holland for helping me score those!), various adjustments that always seem to accompany an old car purchase. Now the main stuff is done.
I have only had it out three or four times (3-4 times more than either Pantera incidentally) but so far it's been FANTASTIC. The car is fast, stable, handles extremely well for a "luxo" cruiser and makes all the right sounds at a tolerable level. It's even quieter with the windows closed. A huge trunk and big, comfy seats that you can easily get into (yes, I'm getting old) and out of make it a classic you can actually live with. The 5-speed is very nice and it accelerates almost like a silver '74 Pantera.
And I KNOW the brakes work REALLY well because my friend Denis was driving it and mistook the clutch for a brake pedal. 
Pretty dramatic to be driving beside your own car when it goes into full lock-up! 
I took the car to our annual Italian Week celebrations and I got a lot of very nice compliments on the car. During the driving parade though "Little Italy" that occurs as part of the event, there were a few puzzled looks trying to figure out what the car was — many more when they heard it zoom past with that deep Cleveland rumble.
The next day I fulfilled a promise to take it to a small car show another friend organizes. It's mostly 50's and 60's American cars so I felt a LOT out-of-place with my "modern" Italian machine. Everyone was really taken with the car though. It was fun to see the looks on their faces when I answered (what year is it?) that it was a 1978 — especially since I was parked beside my friend's 1978 AMC Gremin. What a design contrast!
I'm really quite shocked that I ACTUALLY get more interest in the Longchamp when I stop for gas, coffee etc. than I usually do in the Panteras. And I thought it would be a "sleeper" that everyone would ignore while I had fun. Nope.
In short, I love the Longchamp. You guys likely would too.
Mark