I find A Beka to be repulsive and mind numbing, especially the math and science. For mathematics up to Algebra (exclusive), I highly recommend Singapore Math. Its design is simply ingenious. It teaches math conceptually, of course (any other alternative is deficient), but it lays the foundations for higher maths well in advance, training the mind to think mathematically. I cannot extol its virtues enough. Singapore also has free evaluation tests online to see just which level is best for your student-child. I have heard from others, though, that if you (the parent-teacher) do not know your math very well, Singapore will be a challenge to teach, since it doesn't teach by rote. My answer is, go back and learn math better yourself, if necessary; needless to say, I won't win any popularity contests with this attitude, but I think this is what's best. Parents unable/unwilling to teach math properly tend to resort to curricula based on rote, especially Saxon and A Beka (no offense to newbies who don't know better). Such parents do their children great disservice, because they will likely never truly grok math.

For Algebra and beyond, I tend to ditch curricula, preferring to do highly interaction teaching instead. As a huge leap in abstract thought accompanies these levels of math, I find intense teacher-student time is best to insure proper understanding and retention. I do use books to provide just problems to be worked, though, though I assign the minimum number of problems (the hard ones, of course) necessary to demonstrate mastery. I tend to prefer Schaum's Outlines for my problem books. This approach, of course, assumes parent-teacher mastery of the concepts, much like Singapore does at the lower levels.

For science in the younger years, there's really not much you need to do but merely introduce the concepts of science (e.g., observation, hypothesizing, experimentation, etc.). The real science will come later. (Note that I'm following the classical model here.) For the young ages, actually get out and observe nature and the environs. Look for passing interests in this topic or that and then go buy books (not textbooks) about those topics to explore with your student-child. If he's interested in weather, capitalize on his interest and explore all the elements of weather. Ditto for geology, biology, anatomy, etc. The grammar stage is not really about grokking science, but merely being introduced to the concepts. To this end, experiments should be similarly informal. Watch ants crawl, then place obstacles in their way and observe, noting any changes in behavior. (Don't anthropomorphize, though.) Fun ideas would include finding different rock samples, exploring caves and describe how they're made, watching animals, raising butterflies and ladybugs, building a model of the human body, discovering friction and gravity, experimenting with temperature, etc.

When it's time for "real" science, I recommend Apologia. Apologia has textbooks ranging from 5th or 6th grades (or the equivalent of what 5th and 6th grades used to be in schools) through high school and then some. Yes, they are textbooks, but they're well done. There are numerous experiments that can be done with mostly household items. There are helpful mini-quizzes (single questions) littered throughout each chapter to see if the student-child is grasping the concepts. There are plenty of practice problems and even tests if you insist. We don't tend to favor a textbook approach generally, but science seems to present better this way (at least in the logic and early rhetoric stages).