Of all the related conditions, is blocked tear duct one of the better or worse ones to have, in terms of effects on health and well-being?

Better. A lot of infants have adhesions of their tear ducts. The vast majority of which resolve on their own. Rarely, a child may need to have the duct surgically repaired.
Neither. A blocked tear duct can result in unwanted tearing either intermittently or constantly. Infection can also develop. If this is a constant problem with infection this would have more of a negative effect on a person's sense of well being than if it is an intermittent problem. An eye examination is necessary to determine if there is a blocked tear duct as well as its cause and treatment.