I have used MFW K and 1st grade, as well as the Ancient and World high school levels, but not the five in between levels. I have owned them all at some point, but didn’t use them. MFW is a very solid program and I do recommend it for those needing a schedule or wanting pre-made lesson plans with a literature approach. We have also used Sonlight, but I much prefer the MFW instructor guides over SL.
We stopped using MFW because I wanted to build my own program. I like planning, actually better than teaching 🙁 At that time, my younger kids moved into the TruthQuest guides mixed with some Beautiful Feet and my older high school daughter moved into a combination of things, including Beautiful Feet, which is my favorite of all history programs. She much preferred the BF books over MFW. She also said the BF study guide questions were more “thought provoking” than MFW. The upper levels of MFW are based on a textbook spine with less lit and living books. My kids all prefer the living book approach.
I have never used SCM as written, however, I did build a program from the Ancient level when my kids were very young. I think the major benefit of SCM is that it’s most easily adaptable for large families or families with kids multiple ages. I know MFW and HOD have add on programs, but SCM has it all in one guide. SCM is also much more cost effective. One con may be that it would only be a history/bible guide. You would still have to add science, which is included in MFW. On the other hand, there is not much in the way of formal science necessary in the elementary years.
Again, I think any one of these programs mentioned is going to be solid academically. It’s more a matter of whether you want to build your own and are looking for an all in one vs. parting out each subject. And, whether or not you’re teaching a large family or have kids with a large age gap that you want to keep together. Budget could be another factor. MFW is pricey IMHO. Be sure to look at second hand options.