Laviathon,
Like all audiophiles, I eventually upgraded. :-)
I had the 7140 for about 20 years and it worked just as well when I sold it as the day I bought it new. In fact, it was the last original piece out of my system, as I first bought a power amp and used the 7140 as tuner/preamp only, then bought a preamp and used it as tuner/phono preamp only, then bought a phono preamp and used it as tuner only.
My current stuff is better in all ways than the 7140, but cost 10x. It's been worth it, but I was happy with the 7140 for 20 years, so it was doing a lot of things right.
I saw and heard a 3080 in a friend's system in college and was my first experience with NAD. It was a beast and considerably more expensive than my 7140. My impression is that it was a pretty high end piece and probably way better than the 7140. Too many years apart for a detailed comparison.
David