The only Harryhausen movies I've seen are The Beast from 20 000 Fathoms, The Valley of Gwangi, and One Million Years B.C.. All of them were great movies.
Like I said before; what makes Harryhausen so good is that he could take the most fake-looking model and make it seem real. Winston could make anything look real as well yes, but he had CGI which is more conducive to the task.