I hear a lot about Saxon Math, so that's where I started my search. It looked good to me in their descriptions, so I ordered all of the materials (teacher's book, K calendar, and manipulatives). But when I got everything out to look at the lessons and so forth, I didn't like what I saw. Everything was scripted (something I'm not to keen on, especially in math and science), and it seemed like it was meant more for Pre-K then Kindergarden ("These are called bear counters. What colors do you see? What is your favorite color? Let's play with them for five minutes and then put them away until the next time where we will do the same thing"). The lessons, in the attempt to cover everything, progressed slowly. Only about half way through did it give any sort of "real" math.
While I had been waiting for the Saxon stuff to come, I came across another curriculum, Horizon's Math. Like Saxon, it used a spiral method of teaching with lots of short reviews. It had no scripting (which appealed to me), all of the manipulatives used were easily found around the house, and the workbook pages were colorful and attractive. It was also rated highly by other homeschoolers. So, I decided that I would order that curriculum as well and compare the two, sending back whichever I decided not to use.
When I compared them, Horizons won hands down. Not only was it less expensive, but it progressed at a good pace and wasn't dumbed down in order to cover "everything". By the end of the first month we were starting addition, telling time to the hour, and reading calendars. At the end of the year, we were working on subtraction, skip counting by 2s, 3s, and 4s, and reading clocks to the five minutes. Things also covered were counting to one-hundred by 1s, 5s and 10s, counting money using pennies, nickels, dimes, quarters and dollar bills, measurements in centimeters and inches, and introduction to gallons, cups, liters, quarts, word problems, and a number of other things. I really, really liked it.
My only gripes were that, I felt, occasionally they would introduce too many things at once and that I found little use for the instructor's manual.
We are now starting the 1st grade set, this time without the teachers manual. The lay out is a little different, and they have added tests every ten lessons or so (I haven't decided weather I will use them or not). The curriculum promises the same spiral method and advanced speed. I'm optimistic.
Other reviews can be found at Homeschool Reviews.