Sorry, been busy as all hell the last few days with work, I’ll try to get to the rest in a bit:
Ketch, all the way as that was my intro character to the series. I think it also matched up with what I see as the essential details. Namely, unlike characters like Spiderman who have a secret identity that they can just peel off when it suits them, the Rider is essentially chosen to bear the burden, and he doesn’t have a secret identity, he’s got a real dual personality. When the blood of the innocent was spilled Ketch didn’t so much choose to become Ghost Rider as he was compelled to do so, and once that transformation was complete he wasn’t Ketch with fancy super powers, but the Spirit of Vengeance had taken over his meatbag body and begun using it for its own purposes. In fact at times when Dan was grievously injured, the Rider itself was not only the dominant personality, but Dan was nearly too weak to even talk to it for long period of time.
Which brings me to another essential detail, which is that the Rider isn’t about doing good and fighting evil. Hell, he’s not even really about fighting evil when you get right down to it. The Rider is about vengeance, pure and simple. His Penance Stare is not a way to fight bad guys, it’s a way to inflict the suffering that anybody has inflicted, be they good bad or in between, back on that person. The Rider is an agent of divine punishment (or demonic punishment, although they kind of retconned that with The Blood and the Siege of Darkness and…) But it’s not a way for the hero to live out his fantasies of justice and awesomeness, but for the vessel to become a conduit for Vengeance itself.
Ketch was, himself, deeply ambivalent about the use of the Rider, both trying to use it to “fight crime” and being appalled at what the Penance Stare actually did to criminals. As a direct result of his using the rider, his sister was murdered by Blackout, almost in direct contradiction to Spidey’s lesson with his uncle. Ketch, multiple times through the series, wrestled with what it meant to be host to the Ghost Rider and whether or not he was willing to accept that burden.
Blaze, on the other hand, never really interested me. A hothead thrill seeker who signed a deal with the devil because, hey, what the hell. (well, there was more to it than that, but still…) Blaze was an accomplice in his own situation, Ketch was acting with the Rider all but forced on him. Ketch, to me, always seemed a lot more human.
/$.02