it'd be hard to compare to a modern frame, as there isn't really anything comparable.
Geometry, materials, suspension are all but unrecognisable compared to how a 25 year old bonded frame would have been built up.
As far as I can remember, early frames were just built in the workshop, they should really have been in a clean room.
Later ones, the bonding was more controlled, but still subject to greasy finger prints, tea breaks and so on.
As stated above, if it's lasted this long, it's obviously a good bond. But unfortunately, you them get in to long life issues with the glue!