1) Here's one short piece (by a good SF writer herself, Joan Slonczewski) that has some nice insights into the series (mild spoilers for the later books): http://biology.kenyon.edu/slonc/books/butler1.html
2) Here's another, briefer piece: http://www.tor.com/blogs/2009/09/octavia-butler-re-read-dawn
3) Here's a great 2-minute video by Nora Jemisin (one of the foremost contemporary black spec fix writers) on the importance of Dawn and Butler: http://www.sfsignal.com/archives/2012/11/video-n-k-jemisin-on-the-significance-of-octavia-e-butlers-dawn/
4) Here's a brief framing of the book in terms of agency / autonomy: http://mchrist9.onmason.com/2011/10/26/give-and-take-in-octavia-butlers-dawn/
5) And here's a brief piece considering Lilith's monstrosity: http://www.siueblackstudies.com/2012/10/the-dawn-of-octavia-butlers-monstrosity.html
Optionally, if you're interested in taking a look at something more dense, here's an academic article on the series, considering the value of it as an origin story (which many feminist theorists find problematic):
http://www.depauw.edu/sfs/backissues/65/peppers65art.htm