Personally, I am allergic to cults. Being a member of a cult is not good for your mental health and your well being in general.
Cults
Cults take away personal responsibility. Cults absorb personality, money, and freedom from its members. Just a waste of 'time' and unnecessary suffering. If you want 'to learn a lesson' it can happen in so many more respectful ways. Well, except when you want your ego destroyed, then you're exactly in the right place you are supposed to be. (/sarcasm)
Eckankar
Now to the Eckankar. I don't know them. So I went to their
website, and I googled to find
testimonies of ex-members of Eckankar. If you want to judge a group for being a cult/sect, never start with the content. First, find out their foundations, their structure.
Why is Eckankar considered a cult?
Well, ... a lot of red flags were waving in the wind.
I. The
holy leadership to start with (called by titles like the Mahanta, the Master, Sri, the Prophet).

source:
https://www.eckankar.org/abouteckankar.pdf
II. The
secret knowledge they can offer you that is not available through other means than by their programs.

source:
https://www.eckankar.org/abouteckankar.pdf
III. The
elitism. They call themselves the Eckists to distinguish from the rest of the peoples.

source:
https://www.eckankar.org/abouteckankar.pdf
IV. Initiations

source:
https://www.eckankar.org/abouteckankar.pdf
V. Scientology Church
A very interesting red flag is the fact that the founder of Eckankar, Paul Twitchell, had been a member of the Scientology Church, just years before founding his own church. It's not even a secret, they're kind of proud of it.

source:
https://www.eckankar.org/Masters/Peddar/hisStory.html
My opinion
Well, this is my harvest so far and personally, I don't feel the need to investigate the content of Eckankar. Between the lines on the website, I read about us being particles of the Divine (I agree) and some other stuff I agree or disagree on. I know enough about cults and their way of working. First, it starts with the love bombing. A recruit will be welcomed bathed in love and understanding. Not one single dark cloud on the horizon. In the beginning, they don't even realize it's a real cult until it is too late. This honeymoon period can stretch out over years. It took someone I know 7 (!) years to realize this (another cult). It's a highly complex of psychological processes that make the person stay in the cult. It is a myth that people need to be locked up in order to stay with the cult. If the brainwashing was performed effectively, they will declare it's all out of the free will.
Testimonies from ex-members
I did look up the internet to find out if there are former members of Eckankar and yes... there are ex-Eckists full of rage. Suprise...
Sources:
https://eckankarlawsuit.jimdo.com/ex-members-1/
http://truthabouteckankar.blogspot.com/ ,
http://www.forum.exscn.net/threads/eckankar-–-a-scientology-clone.31226/ ,