As I've mentioned previously, I homeschool through my state's option of being registered with an umbrella school. The umbrella school I use does have requirements as far as high school goes in regard to English credits. Four credits must be earned and each year must consist of writing/composition, literature, grammar, and vocabulary (with a heavy emphasis on the first two components).
We made the switch to IEW for writing/composition last school year in the middle of 8th grade, and I have been so impressed (not to mention deliriously happy) that I chose to go with Fix-It! for grammar. Specifically, my son is doing The Little Mermaid ... yeah, he wasn't overly thrilled when I made that announcement on the first day of this homeschool year, however, he's doing wonderfully with the program and has commented time and again how much more he is enjoying this than anything we've ever used before. Although each Fix-It! lesson does require the student to define specific vocabulary words, I wanted something more in-depth and opted to use an additional resource to cover that need.
For vocabulary I was honestly at a loss when planning for this year back in the spring. Throughout the years we've used probably three different vocabulary curricula, none of which were met with much enthusiasm. This year my son is working his way through Vocabulary for the High School Student. He does a short lesson daily and loves the book. I mean really loves the book, as in he is finding it highly amusing to work the vocabulary into our conversations and then proudly announces to me with much laughter which words were from his recent lessons. The book is lengthy enough that it will take him through a significant portion of 10th grade as well.