The first X-men movie, albeit good, was something of a dissapointment in terms of some of the characterization for me. Both Spider-Man films got Peter and his supporting cast spot on, minus spidey's humour though. X2 was awesome but didn't erase the problems I had with the first. Thats why I voted for Raimi. I also think Raimi cares more about and pays more attention to the subject material
Singer has my vote. For one, he's just a better director overall. He also kept more of the comic essence with his two X-Men films. Raimi's two Spiderman films had a lot of things that shouldn't have been. Ock was being controlled by the tentacles instead of the other way around, Ock turned good at the end, Spiderman has organic webbing, etc. With Singer's first two X-Men films he didn't make things up or make BIG changes to things from the comics. Spiderman 3 already looks like it won't be better than Superman Returns. Lastly, Raimi needs to take a few lessons from Singer & stay true to the comics instead of making up his own bullshit, it's only making fans madder & madder.