I guess I start with the fact that this is a movie, not a filmed stage show. That means the sets are lavish, realistic and expansive. The singers move around a lot; there are horses and carriages to take people to Paris; the singing is uniformly well recorded, and Alfredo's family are brought into the opera without interrupting anything. The street band is filmed in a street, and the gypsy dancers have room to move. There are little visual asides, which can only be done in a movie, such as the old woman stealing a small box as the party ends in the first act.
The singers can and do act their parts. Violetta may very well be dying of TB. Teresa Stratas is waif-like, and fits the part perfectly. There's nothing waif-like about her singing, though. She's full-on; as strong as any I've heard. Placido Domingo is youthful here, and again fits the part perfectly, as do the other singers.
I'm told there have been cuts made to this version of La Traviata, but to someone like me, who can't quote the score verbatim, they're not apparent.
In short, if you want to see your opera as well as hear it, you can't go past this recording.