ALB.....My dd is 4.5 and we are using the same exact curriculum. ETC Book 1, HWT, Saxon Math 1 and FIAR, so I'm so glad I found this thread!! :) We LOVE LOVE LOVE Saxon....and yes, I've questioned it, just this past week I questioned Saxon Math 1, you can ask a good friend of mine...she had to listen to me!!! I questioned Saxon K when we started and one thing I learned is that you have to give it time. At first, I did not understand where Saxon was "going" so to speak, but after you get about 1/4 of the way through Saxon K it clicks!! I've tried to supplement Saxon twice and it never worked. Saxon is a very solid program. I've got caught up into thinking that I needed two math programs because so many people do use 2 math programs, but Saxon doesn't need another program to go along with it. My dd learned so much in Saxon K and now that we are in Saxon Math 1 she is loving it. We tried RS and it wasn't a good fit for us, but I did get the RS game kit. I've never looked at Miquon, so I can't say about that. My dd catches onto things really fast and could easily use a mastery program, but for some reason she just LOVES the spiral from Saxon. I figure if she's loving it and learning, then I need to stick with it.
I hope this helps....:)