+1. The lugs add extra mass, but it takes a fair amount of braze to build the joint up the way people like it with fillets. Silver fillet brazing, which is currently out of favour a little, is both light and low heat, as if the latter mattered for the most part. But it ends up looking like a tigged bike, and there have been allegations of cracking. From a practical perspective, if I didn't want a welded frame (so only so practical....) I would choose lugs unless the geometry dictated otherwise.