QoinPro is the only one of those sites that I've heard of -- and it is of questionable legitimacy.
I'll be waiting until a major wallet or exchange supports this or any fork (e.g., BCD, BCG, BCH, BCP) before I have any concerns about claiming.
Agreed. QoinPro do not reply to emails, tickets, or twitter and do not offer 2FA. I won't be sending them my BTC till they do....