Question @Best_Change:
If you take a look at exchangers list, most of them are with 0 (ZERO!) negative reviews, because if you post negative review they invite the exchanger to comment and all that exchanger have to to is to click "cancel claim" and your negative review becomes a comment.
Is this true? If so, that makes the review system worthless, but it does explain why there are no persistent negative reviews on any of the exchanges you've listed.
If this is indeed true, can you publish this as a warning in bold on the review page? It seems misleading to omit this.
I remember I used bestchange a year ago to exchange something from one if the sites they publish. The site didn't send my money for a day so went and put a bad review after that the site came replied my review then automatically the bad review is gone.
All it takes to remove a bad review is just the site owners to respond no matter what automatically it will be gone.
So i guess the op is correct from my experience too.