Whilst A,B,C would indicate high standards and results - you would avoid D ! Even if he has posted a few good results, is a member of the coalition, member of ISHRS, has a great CV and impressive website.
Mop, if a doctor who is a coalition member and still a D why should he be in the coalition list in the first place??????????? The idea contradicts what this website stands for.
If they are recommended here then go for those doctors (its as good as them getting an A or B)