I have used Word Voyage for years and love it. The program is not super fancy, but it teaches the fundamentals of English: vocabulary, Latin roots and grammar extremely well. Best of all, I get to check my children's sentences and make sure they are following through. Some other programs claim to check grammar and word usage accurately, but we all know this is marginal. Word Voyage makes it very convenient for me to verify the work and assign revisions as needed. My kids know I can do this, so they almost always pass in perfect sentences the first time. They've learned that details matter!