This is just my humble opinion, so take it for what it's worth. I've bought LLATL for my children 3 times and resold it. The more I looked at it, the more it wasn't a fit for us. I wanted something that was gentle, that utilized picture study, that taught grammar, that used dictation and copywork, that encouraged creative writing, and that the children could do independently. LLATL fits some of these things, but with three children having to pull out 3 teacher's manuals and keep track of all that was too much.
The little books by Serl (Primary Language Lessons & Intermediate Language Lessons) were good but my boys hated to have to copy things down from the textbook. I LOVED English for the Thoughtful Child, but that only went to a certain grade. If this would fit the ages of your children, I really recommend looking into that! They even have the child do some nature study!
But my children are 12, 10, and 10. What I ended up with was using Sandi Queen's Language Lessons for the Elementary & Secondary Child for the grammar. I use Spelling Wisdom for copywork and dictation and it's going GREAT!!!! This combination has such a CM feel to it. The Language lesson book is great because it will have the child write a story based on a picture (in color) every once in a while. This opportunity for creative writing was what all the other books were missing. She LOVES this. It's not too burdensome for the boys either. Spelling Wisdom is going SOO well, also.
Just some more things to consider. Take a look at your children and their ages. Think about what you want in a grammar curriculum and why. Think about how much time you have and how much you want to put it into a program as the teacher.
I do have a friend who uses LLATL and has loved it and convinced me 3 years in a row to buy it, but I never even got past one lesson. At least certain stores have a good return policy!
Hope this helps in some way.