Poetic
"A vampire in love with the slayer. It's rather poetic... in a maudlin sort of way."
Angel vs. Spike
Buffy has had two vampires who have loved her: Angel and Spike, this is a comparison between the two.
Both are vampires, so let's just say that neither one could give Buffy a "normal", healthy relationship, but then, Buffy could never give a regular guy that either...
Angel, turned by Darla in the eighteenth century, was one of the most fierce creatures ever to walk the night. He was cursed by a group of Rumani gypsies after he fed on a beloved daughter of their tribe. They restored his soul. He's forced to walk the earth for the remainder of his eternity feeling the remorse of his deeds. He lived like a homeless person on the streets, feeding off rats, until he was shown a different way by a demon named Whistler. He was shown the newest chosen one - Buffy, and he loved her. He decided to change his life in order to help her.
Spike, turned by Drusilla in the ninteenth century, was obsessed with one thing... killing slayers. He had killed two, one in China during the Boxer Rebellion and one in Manhattan in the seventies. But when he tried to kill Buffy, things were different, she had friends and family, something no other slayer had before her. But like Angel, he would also be cursed. Not the magiks of gypsies, but by technology. A chip implanted in his brain by the Initiative would prevent him from hurting humans. Finding that he could hurt demons, he forms a reluctant bond with the slayer that leads to his eventually falling in love with her.
So both now have reasons to be "good" forced upon them, but still Angel comes out better in Buffy's estimation because of his soul... So lets look at a couple different perspectives...