Here is what I have to offer on this matter....hope it helps a little!
We used much of ECC.
Here are some of the reasons that HOD is a better fit for us than MFW.....
--HOD truly includes ALL subjects/lessons into their guide. For example, I don't have to schedule in the recommended Language Arts lessons myself into blank boxes on the lesson plans page.
--HOD helps me make the mental connections with God's word as the teacher so that I can relate that to my children with each lesson. HOD really connects everything back to God's word in each lesson box.
--Like someone else said, I do not have to do book basket. All of our reading is close at hand for those times when the weather is too bad to go to the library, or the kiddos are sick (which happens a lot in our house during the winter

).
--Everthing is truly at my fingertips with HOD- no hunting the stores for extra project supplies. That is not always a bad thing to have to do, but there are just too many times for me when I don't have time to "hunt and gather".
--I found that with each level of HOD the books in the package are really true to that particular age level. Whereas in MFW ECC, I found some of the books to be too old for youngers and some of the books to be too young for olders. Not to criticize MFW....its just that it did not work for us.
--I found that HOD guides contain a wider variety of activities and assignments, and appeals more to the different learning styles. HOD seems much less "worksheet" oriented to me.
--Last but not least, the HOD book choices are just wonderful! That's a major "bottom line" for us!!
--There are several other reasons, but these are just a few!!
Also, I want to say that I really respect MFW. They are a great company! These are just the differences that popped out to me, and why HOD is the better fit for us!
Hope this helps you!