The customer list is in the ATF's hands, but through the legal process, it will be returned.
But, that customer list is only from before March 2014. Any new customers after that time are cannot be accessed by the ATF since the ATF does NOT have ongoing access to Ares servers.
Also, Ares upgraded their infrastructure, after the raid, and now all customer data sits on encrypted hard drives. Even if the ATF were to seize the records, again, the government cannot compel anyone to unencrypt their information.
So, you information is actually safer with Ares, than it is with a lot of other websites out there.