Quickseller's rating is abit not correct because they are not putting their investor in risk it seems.
Did you not read about them first refusing to pay for a bug bounty so they can fix a +EV method to win on their site? Did you not see how, even after the +EV method leaked, that they didn't understand how it would cause them to lose? Did you not see how they are still refusing to pay to have Dooglus disclose the bug that he separately discovered (which would also cause the site to most likely leak it's bankroll)?
I am not sure how you think that investors money is safe on this site. I am not sure why you think it might be a good idea to invest in this site if you were to trust them enough not to steal from you outright and if you were to trust them enough to not play against the investors.