i just heard the scams done to some peps
i am thinking to invest a bit in ckminer.com
is it ponzi system site?
should i invest in it?

and please drop some legit cloud mining sites below
Hashnest.com here is the only legit one in my view, and if you go there and buy some GHS you will see that you will make no profit in the long run. Hashnest is backed by bitmain the producer of the Antminer S9 so if you cannot make any profit with them how do you think will make profit with others ?
All others who promises profit in this area are pure scams. Stay away.