I have a 1980 CanAm 400 MX-6.
All can ams are truly fast for their size. All were strong and had high quality hardware.
The late 70's orange ones handled very well for their day, with excellent suspension.
The 1977 black ones were okay handling.
The '76 and earlier white ones kind of handle like a refrigerator that fell over, but are fine on the trails.
IMO parts availability is the only problem.