It took me a long time to press the button too. I really wanted this curriculum, but I abandoned my cart a number of times before I purchased it. I had been using BFSU, but wanted something a little easier to use. I think Nancy Larson is a good, solid science curriculum, but I still prefer BFSU and have returned to using it.
I don't like the scripting in NL. I like some scripting (as in AAS) but NL is completely scripted. I thought I could use it in spite of this, but I find it annoying. This could be due to the fact that I have a background in science and winging it (to a certain degree) is fun for me.
I also don't think the hands on activities are very hands on. I'm speaking of level 1 - the other levels lend themselves more to hands on activities, so they could be different. There are a number of fun items in the box, but many of the lessons rely on picture cards. It just feels too much like the science I had in school. I prefer real world discovery to plastic bugs and pictures.
Those issues aside, it is a solid, easy-to-use curriculum. It has great breadth of coverage. It has motivated me to stay on track - which is huge because we didn't do that before. I can see that this might be particularly appealing to a parent without a natural inclination or background in science. You can teach solid science with this curriculum without background or preparation. It is truly open and go.
I just can't justify the $263 per year when I purchased BFSU for $25 and it includes lessons from K through 2nd grades.