The EE days have only changed once, when WDW did away with them for a while and brought them back on different days. Other than that, they stay the same. They are:
Sunday: Magic Kingdom
Monday: Animal Kingdom
Tuesday: Disney Studios
Wednesday: Epcot
Thursday: Magic Kingdom
Friday: Animal Kingdom
Saturday: Disney Studios
Whether they are worth doing or not is up to you. Even though they are available to anyone staying onsite, the parks are not crowded at all during that time. However, the EE park will become more crowded than the other parks later that day. So if you enjoy getting up and hitting the parks early, you could do EE then hop to another park when it starts to get crowded. Or if you do not enjoy getting up early, then you can go to a non-EE park. We do a combination of EE days and non-EE days each trip, depending on what we feel like.
Happy planning!