I don't understand why if they are a legitimate company they would go to such lengths to hide who they are?
Its interesting too the heat map of where most of the traffic is coming from -
http://btc-arbs.com.hypestat.com/42+ percent comes from Russia. I also noticed the Perfect Money deposit account is NOT Verified
Hide themselves in the hacker infested bitcoin world? Doesn't seem any different that most bitcoin sites. However that doesn't mean they are good or bad. There have also been plenty of very public scams.
Frankly I don't see the point of comparing btc-arbs and bitcoin trader sites. They both could be scams or they both could be fine. Comparing them doesn't prove anything because you can't be 100% sure either is completely safe.
However I'm 100% sure that when someone posts a huge argument supporting one site or other with a referral link, there is a good chance the intensions are just getting referrals.