Trek.
Not because they make a bad bike, but for what the company and it's president did to Greg Lemond. They protected a liar (Lance Armstrong) and punished a good and innocent man. Armstrong wanted Lemond put out of business for going so far as just to hint that Armstrong was not clean. Trek complied with Armstrong's wishes.
Back in his TDF days, Lemond visited the shop where I worked. There was no entourage or body guards, just a friendly and smiling young man who shook everyone's hand, and autographed most of the magazines and bike seats in the shop during his visit. He was a genuinely good person, and I cannot forgive Trek for hurting Lemond to satisfy Armstrong's ego.