Well longer hubs are more popular with the Admin here it seems. But I like the shorter 'sweet and to the point' hubs. I also like hubs that have links to them to either other hubs or other pages. I'm not too keen on reading something too long because I'm not on hubpages to do a 'study' of a person's hub. It's just to read something interesting, fun and/or informational.
The only time a long hub will catch my interest is if for one, it's something I'm seriously interested in read. Two, there are pictures and diagrams to keep me interested and three I'm writing a hub on the same subject and need a different perspective (or I want to make sure no one else has written something similar).