I don't post here a lot, although I do read these forums a good bit. But I wanted to just comment a little on your struggle to decide between the 2. I have similarly struggled very much in trying to decide the best course. My oldest is a senior and just today I was mentioning MFW, hadn't talked about it in months, and she surprised me by saying that she wishes we would have done that. She's doing SL Core 400 this year, and likes it, but really liked the simplicity of MFW, which we did in her 7th and 8th grade years. I vacillated between MFW, SL, and TOG for my kids, and tried TOG a good bit. Here's how I sum it up - with SL, I feel behind most of the time and that there's something more I want from it but can't quite put my finger on what it is. With TOG, I just feel overwhelmed. Stressed when I do it to the full, guilty when I slack off and try to be relaxed. It has such a heavy emphasis on historical analysis that it took the joy out of history for us. For some people, that might fire them up though. The times we used MFW, we felt just right, like Goldilocks and the 3 bears. You can easily add SL readers to it, it has hands-on that you can choose to do or not do, the TM is just right, the work load is just right, and because of that it can feel too light compared to the other 2. But I actually felt satisfied with what we accomplished when we did it.
I am doing SL with all 5 of mine this year - have used it for the past several years, but am missing the simplicity and hands on of MFW, which my kids would choose also if I laid it all in front of them! My oldest loves to read so SL has been good, and she admits that TOG was more rigorous, but she just said today that if she ever homeschools, she'd like to use MFW. I was surprised!
I would love to do MFW ECC with my younger 3 next year, which I do have already! And no idea what my rising junior would do, maybe just finish out with SL like his older sister. Hope some of this helps!