The quality of the Bonds and the quality of the films they appear in are all over the place. Traditionally my answer would have been Connery as the best but upon recently rewatching the entire Eon series, I liked Timothy Dalton the best.
Connery is charismatic but often let down by cheesy scripts and by the end of his run he was redefining what it mean to not give a fuck about the movie you were in.
Lazenby only had a single role, and he was not good in it. The film he was in was good, but not because of him. He might have matured into the role later on, but unfortunately never appeared in any others. I would have been willing to give him another shot.
Moore is entertaining, I don't hate him necessarily but he took the silliest parts of Connery and made that the core part of his character. All of the camp of the final Connery films was extrapolated through to Moore and amplified over time as the series became more of a parody of itself. When Austin Powers is making fun of Bond, he's making fun of Roger Moore for the most part. The pinnacle of decadence in the series was achieved during Moore's tenure, when they go to outer fucking space and have laser gun fights. They wouldn't reach that level of absurdity until Bronsan's final entry.
Dalton was the first time the franchise realized it got too fucking silly, stopped, and took a slightly more serious approach. He counterbalanced Moore's camp, and his second outing is really god damn dark by the standards of the early series. I personally consider The Living Daylights to be the finest James Bond film ever made. I don't know why exactly but I just love it to bits. Good performance, relatively interesting plot, good supporting cast and good villains. It's not too crazy although it's not perfectly serious / gritty either. License to Kill is an interesting experiment in going dark, someone described it as an episode of Miami Vice starring James Bond and I guess that makes sense. I like it, but it's not a favorite. Still, Dalton was awesome as Bond and it's a crying shame he didn't get a chance to do a third film.
Brosnan was my fave as a kid, since he was my Bond when I was growing up in the late 90's and early 00's. I still don't hate him, but realistically I only like two of his films, Goldeneye (the obvious best) and The World is Not Enough (not great but I like bits of it). TND is a bit shit and Die Another Day was abysmal. So bad and so ridiculous it once again caused a back to basics approach in the next film. He's very likable, although not the best actor in the world.
Craig is a good actor, but I don't personally like his Bond very much. Nor do I like his movies a lot. Hated CR when it came out, and although I've softened on it upon reviewing it, I still don't love it. QoS is garbage. Skyfall is good. Spectre was so so. I'm glad they've returned to drawing upon some more classic elements, but they didn't do it well.