I think that I have read every single "Seth" book that there is! And some of them I have read many times. I used to be very into it! I had read all 4 Original "Michael" books, some of those more than once also.
"Seth" says that he Only channels through Jane Roberts, (The author of the books , now deceased)
The 4 original "Michael" books were by Chelsea Quinn Yarboro (also a sci-fi fantasy writer). Since then , apparently other people are claiming to channel Michael, and there are some books out now by other people. I bought one but haven't read that one yet. I'm not sure what I think about other people channeling Michael BUT I would suggest that if you are interested , you at least read the original books First.
Maybe these 2 have similarities , but there certainly are differences. Seth is more of a ..........personable story teller with a lot of interesting psychological type information. A lot on reincarnation , art , health . I don't know how to describe him exactly , but I must've found it very fascinating to have read the books so much!
I guess I found Michael fascinating too! Michael is a little more into organization , classification , numerology. He organizes souls, spirits, higher selves (or whatever you want to call it) into groups whose organization and classification is detailed and corosponds to numerology. A lot on the progression of the soul reincarnating into lives also. Also classifications on how you are looking in This life. I found some of it hard to figure, or hard to figure out what I am and where I stand according to all these classifications BUT believe it or not , there is a person who will actually channel this for you personally now!