Hotspur:
I've often wondered whether a story should be judged on the number of times it's taken as a favourite or by the number of comments
An interesting question.
I don't think it's an "either/or" situation. Some readers will not comment, but apparently will mark stories as a 'favorite.' Others - particularly those who comment a lot - will use 'favorite' designation more sparingly, possibly because of the total number of stories they read. So I think you have to look at both.
Interestingly enough, the stories by some authors, when taken as a whole, have generated almost as many 'favorites' as comments, or even more, while the stories of other authors (me being one of them) have several times as many comments as 'favorites.' I don't know what factors there might be that cause one author to appeal to 'favorite'-designating readers, but another to appeal to comment-making readers.