There's also a lot of uncertainty about them because they look very different from the list of science stuff we were required to teach kids in the past. Take a gander at what our Illinois standards used to look like and a sample of the NGSS below:
The "old" Illinois Science Assessment Frameworks for Grade 11. 
The new NGSS standards. As you can see, there are now Science and Engineering Practices (SEPs), which are analogous to the mathematics practices in the CCSS. There are also Crosscutting Concepts, or CCCs, (which I always called "themes") that run across multiple units. The Disciplinary Core Ideas (DCIs) are the content that needs to be understood in order for students to meet the Performance Expectations (PEs), which are listed at the top. And those PEs are the critical component of the standards - they are what students should be able to do when they synthesize all of those good CCCs, DCIs, and SEPs. While you do have to wade through all that alphabet soup to understand what's going on in these standards, I believe (unlike some) that they are a step in the right direction from what we used to have. They seem to try and make students use what they've learned instead of just learning disconnected bits of stuff.
And that's why I like the NGSS. But implementing them can be tricky.
I feel that we have to generate some sort of vision of what they look like when students have mastered them rather than hiding behind the "we don't know what the assessment looks like yet so we aren't going to make any changes" excuse. To me, this is what NGSS implementation looks like:
- Classroom instruction must change first. Students need more experience with scientific thinking and real scientific experiences-in other words, students need more experiences doing science to learn about science. The 5E model is a good start with this; you can find a quick handout hereor you can check out this book. Teachers need a clear vision of what learning looks like under the NGSS first and foremost.
- Spend more time in the classroom on teaching students to think with science rather than covering content and trying to get through some District-approved map. Give teachers the permission, flexibility, and time to experiment (pardon my pun) with what's best for student thinking rather than getting through content. Let the content serve the thinking skills and experiences, not the other way around
- After what instruction looks like under NGSS has been nailed down, then start having discussions about what courses and course sequences should look like. There are sample sequences in Appendix K, but I feel these should be used to guide discussions rather than making it look like teachers have to choose one of them. While I personally favor a more integrated approach because it's better for how the brain actually learns, teachers and administrators need to look at the students in front of them and ultimately determine what's best for those students.
