Personally, I like "Blood on the Fields," and I play it more often than "Headhunters" which is okay, but really not something I need to hear a lot. I think the book on BOF and some of the writing and playing is quite good. I didn't think so immediately, I had to live with the recording a few years and get it out from time to time, but it clicked with me and I like its story and the execution quite a bit.
Personally I don't think either are phenomenally important works in the scheme of things, so I've not really voted for one or the other. But if one asked me to vote for one of these, I would not choose the Hancock.