I have read a couple of Zecharia Sitchin’s books. It read as a more plausible explanation for a beginning than what I learned in church as a child. Explaining many of the contradictions held out to me as truth, all questions of them resulting with the answers "He works in mysterious ways" and "You just need to have faith" neither of which inspired me a whole lot.
A couple things that stood out to me (it has been years since I read his work) were the fact that the Annunaki have much longer lifespans and purposely modified our DNA to shorten ours according to his research. This implies aging can be manipulated.
The second is what are the odds they left behind hidden rulers to direct us until such a time that their planet comes around the sun again for them to collect the fruits of our labor? Of course, this also begs the question if they will find our arrogance beyond their patience and decide to flood the earth again as Sitchin claims they did once before to get rid of us.
Zecharia did find something out of these Sumerian tablets. Thanks to him for devoting his life deciphering the code. I've 3 or 4 of his books several years ago but I don't know if he has written more than 4. His books were very interesting though. It opened my eyes to many things that I would not have done on my own.