Okay emeraldcity, I really don't know how to answer your question. Dd loves her homeschool room and spends a lot of time there. I have seen her play with all the science stuff I have there. She also loves the moveable alphabets. She goes to the math manipulative material occasionally but I believe she has picked up a lot by just having them in the room, kwim. She spent considerable time many months ago writing a large (4-digit) number using number magnets and then using the units, tens, hundred and thousand material to visually represent the number and using the Montessori number cards to write the number. Within a few weeks, she could add multi digit numbers in her head and had a solid concept of place value. The fraction sandwich was a big hit and she got a lot out of it. She can easily add fractions like 1/8 +1/8+1/4 in her head because she visualizes it. She had a phase where she was crazy about the multiplication and division boards. Learnt what she wanted. So great, right? The problem is they were all short phases and then they were over. Having said that, I would do it exactly the same way again. She got so much from the material. I had initially thought I would use them to teach her stuff but that never happened. But I think as she encounters more difficult concepts, we will come back to the materials and use them in other ways. So yes I would recommend them as long as you don't care how much or how often your child uses them.
