Choosing between Abeka, BJU Press, Sonlight, Classical Conversations, Memoria Press and the rest can feel like comparing oranges to fruit salads. Strip it down to five dimensions and the decision gets much easier.
Worldview: how central is the Christian worldview — woven through every subject (Abeka, BJU), literature-rich with Christian framing (Sonlight), or lighter with room to supplement (The Good and the Beautiful)? Neither is wrong; matching your family's conviction is what matters.
Teaching style: traditional textbooks, classical (grammar/logic/rhetoric), Charlotte Mason (living books, nature study), or unit studies. These are not interchangeable — pick the style you can sustain for a year.
Classical Conversations and full Sonlight packages expect significant parent involvement; BJU video and Abeka video options shift teaching time to instruction but add cost. Budget honestly: a $300 textbook set is cheaper than a $1,500 video program, but the hidden cost is your hours.
Used-curriculum boards (including the demo board on this page) routinely sell last-year's editions at 40-60% off. For math and grammar, older editions are often fine; for science and history, check for significant updates.
Read the scope & sequence document from each publisher before buying — 'covers biology' means very different things in different programs. Check whether the license permits resale (most printed materials do; online video access usually does not).
Finally, consult your state's homeschool requirements: some states require specific subjects or assessments, and some curriculum programs are explicitly designed to map to them.