Ugh, I know I should be ashamed of myself, but I watch these shows along with my wife - just in the background, though.
Oprah used to be very good, but now she uses her influence to further the things she herself likes and appreciates; her audience appears to be following her too blindly for comfort. She should stay away from political subjects because of that! Right now, I think this show is the worst of the three and I will not watch it AT ALL.
Tyra is, IMHO, more sympathetic as a person. Her show is quite neutral. Not interesting though.
Dr. Phil would be best, simply because he at least tries to HELP others on his show. The people in his show are exchanging entertainment value for help in their private lives.