We tend to move around. One kid likes Singapore, one hates it, but likes Saxon. One hates Saxon, likes Singapore, and for a brief period, liked Math U See. However, she lost interest with the continual repetition, and I personally found Math U See too long , boring and repetitive, so won't buy more of it unless one of the kids insists, which I doubt. I also considered it way too pricey to just fill out a fraction of the pages, but I can see that if your child needs a lot of repetition, which mine don't, and don't get bored, it might work. I made the mistake of buying the manipulatives and dvds, and we have never even opened most of it. I'd read great reviews, but it just did nothing for me and I didn't see my kids move on and make much progress with it, as they got turned off and bored.
At different points, computer programs have worked for my kids, especially ds who hates writing. At one point we dropped all math on actual paper with one of my dds and she just repeated an entire grade of math on Time4Learning, which took her a couple of months over the summer. She just needed a break, and she returned to Saxon with enthusiasm.
The one thing that I have found is that if I try to stick to one curriculum, boredom and sometimes negativity creeps in. If I try to listen to the kids and am willing to provide a variety of books, they find what clicks for them at that point. My 4th grader picked up Singapore 6th grade recently and completed the entire algebra section in just over a week. We will probably use Hands on Equations for a while now, plus order Singapore 7th grade and let her just do the algebra section in that, as she's excited by algebra right now. Then who knows what we'll use? It will just depend on what seems to work for her at that point.
So, we have lots of math books, often random selections, and just as I despair with one thing, something else seems to click for that child. With my quirky crew, I couldnt imagine having just one scheme and sticking with it. I think that eventually you have to take a plunge, buy some different materials, and see what works for you. Just buy one level of each type, as you might find that for all the planning that you do, your kids don't agree. ;)