Allow me to elaborate on certain characters...
Robert: He has two versions out. One (Kashiff Bhatti) is a beta that uses too much stuff from previous KOF games and hasn't been updated for the life of me. The other version (FedeStalker) is more complete and boasts all of his moves, but is sluggish in terms of comboing and has glitchy and improper portraits.
Ryo and Yuri by REJY and Night are in the same category as each other. They do seem to be properly based off the game, but the requirement of adding several KOFXIII system files to my MUGEN is a major turnoff.
Benimaru was just sloppily put together.
Once I can code and the like, I'll make much better conversions (or at least try to).