I never had any problem with Quickseller. Au contraire! I noticed he has a high expertise in Blockchain analysis, as can be seen here, for example.

Observing his expertise in the field, I contacted him once to help me with the investigation about paraipan and the missing 250 BTC and he helped me a lot, as it can be seen from the linked post.

No matter his earlier conflicts here, if the man says he is sorry, it should be taken into consideration... He is trying to make things right and this should be appreciated. As many of you know, theymos also recommended at some point in the past to try to be merciful and try to forget if someone was wrong in the past, if that person trylu regrets. I really believe that Quickseller is honest here.