Before I start , let me note I have never dealt with this vendor.
I think it's ok to share specific feedback of general interest regarding a vendor or product . For example, a certain ballast doesn't work, or requests for customer service go unanswered, or payments are made and no product is shipped and the like.
I don't think it's ok to issue a vague open invitation to bash someone. That often leads to acrimony,name calling , little useful information and a closed thread or worse.
I agree with Gary that disagreements or vague "issues" with a vendor are best handled privately.