Well it's the best they had back then, it's film history - that's different. It was enough to scare me as a kid, so I'd say it was very well done. Even in stop-motion you can do good or bad. The old King Kong is great, but I would not have been positively surprised by a stop-motion Kong by Peter Jackson (although it might have been an interesting experiment).
Another kind of stop-motion I like are films with 'clay' figures, like "Wallace & Gromit" and "Nightmare before Christmas".