I think they are decent for what they are and I think they would be an acceptable replacement. If the kit parts were damaged or destroyed however, I would rate the kit parts significantlysuperior when built up properly compared to this particular item.
I ordered and received some 3d printed fittings for my 1/24 Schnellboot project and as usual was very happy with the products, especially the detailing.
Just purchased some scale twin 50 cal machine guns to replace what came with my Bancroft PT 109, also purchase a 37mm antitank gun and a 20mm cannon to complete a more scale appearance.