Buick for 44 years
While growing up in the mid '60's, we were primarily a Ford family, my Father, however broke from tradition and traded his '62 T-Bird (the car was a lemon) for a '64 Riviera, a totally fabulous automobile, the old Nailhead V8 ran like a Swiss watch.
The Riviera was replaced by a '68 Cadillac Eldorado, which turned out to be another lemon, it was, in turn, replaced by a '69 Imperial LeBaron coupe, however my Dad was totally disappointed by it's build quality, rattles and squeaks abounded in the car.
All became full circle when he got rid of the Imperial for a new '73 Lincoln Continental Mark IV, he's owned Lincolns since, although he would reminisce about the Riviera quite fondly...