Cast lugs are a labor-saving element in frame construction. Stamped and/or hand-cut lugs take a great deal of time and labor to clean up, thin, and generally make them look good. So if what you treasure about vintage bikes is that they are handbuilt craft objects, then stamped lugs are "better." Especially if one finds their inevitable imperfections charming rather than irritating. There are folks within the vintage bike community who greatly prefer bikes built before about 1982 precisely because they tended to use stamped lugs and involved more hand labor (myself, for example); there are also plenty of folks who don't care a whit (or even prefer the cast lugs).