As I replied before, you should understand that you can still use SSLstrip against HTTPS Everywhere. By searching a bit, I also came across this link and this test (related to the previous link), it seems that HTTPSEverywhere does not protect you against spoofing attacks. Related to this topic, I could also find this onethis one which contains a lot of good information, and this oneone on how to protect from sslstrip attacks.
Have fun reading ;)