I will say that there are schools that will take COMLEX only and others that will require the USMLE (despite saying they will take COMLEX scores). My friend did COMLEX only and she had more interviews than I did, however the places that we interviewed at differed greatly. I am not at all saying any residency is better than the other, but she got more midwest interviews, while I got more west coast/southern/east coast programs.
My advice to any future applicant is to 100% take the USMLE regardless.