I loved the Original series (1963-89)
The New series (2005+) has it's moments but not a huge fan.
William Hartnell: starts of great in the first episode of an unearthly child but goes really unlikeable for the rest of the story and doesn't really pick up until the edge of destruction. By then his era is great and despite his ill health in his later seasons he's still a great Doctor.
Patrick Troughton: IMO, he's the best Doctor, a lot of the character troupes used today come from him. He's a master of improv and ad libs so at lot of his best character moments all come from the actor himself.
Jon Pertwee: While a great Doctor, the decision to strand him on earth has the side effect of making the stories quite samey. But the family dynamic of the cast more than makes up for it.
Tom Baker: His first three season are absolutely amazing, but after Graham Williams takes over, it goes down hill. The saving grace of Tom's later seasons is Douglas Adams.
Peter Davison: A very dull and Bland Doctor who doesn't really find himself until his last few stories. A few classics hidden among mostly meh and bad.
Colin Baker: A fantastic actor with some great moments let down by JNT's failed experiments. Colin helps to make the abrasive character work. While given a hard time by fans, his era is mostly ok and doesn't deserve as much hate.
Sylvester McCoy: After a poor start, we get the great chess master Doctor, the one who plans his victories before the story even begins. Thanks to Andrew Cartmel, classic who went out on a high note.
Paul McGann: One of the few highlights of the failed US reboot and really shines in the audios, though the ones with Colin are the best, he comes a close second.
Christopher Eccelston: A strong but flawed start to the new series. Though it would've been nice for him to have more stories, I understand why he chose to leave and think within the story it makes sense.
David Tennant: My least Favourite Doctor. Arguably ruined the franchise, he only seemed to have three emotions over the top whimsy, angst and aggression. Incredibly vain and unlikeable, I fail to see the appeal. I imagine if a unattractive actor played this character, he would not have been so loved.
Matt Smith: Due to the terrible transition from Tennant to Smith, this era is a mixture of Amazing and awful as Moffat struggles to do his own thing and battle those unwilling to let Tennant go.
Peter Capaldi: A great actor let down much like Colin Baker, the character changes with each season and is shafted by Moffat's decision to put focus on the Bland character of Clara.
Jodie Whittaker: The most generic Doctor thus far. Chibnall plays it way too safe and just decided to recycle the tired troupes of the Davies and Moffat era.
John Hurt: Great Performance but honestly didn't need to exist.