I'd like to know how Devil Arms compensate for Alucard's ability to regenerate from the smallest smear of blood, or his ability to totally shapeshift his body into an insane force at will, with no need for any items to bring out his full power, I wouldn't mind so much if more people backing Dante brought hard evidence to the table proven by DMC Canon, whereas everyone who's backed Alucard, has done so.
Dante sure as hell isn't immortal, we haven't seen what would happen if every part of his body were obliterated, leaving only the smallest smear of blood, and because of that, I have no reason to believe that he's entirely unstoppable.
Alucard isn't unstoppable either though, he may not be immortal, but he's the damn closest thing to it, before anyone puts the point to me in particular, I'm aware this is a DMC bored, and as such, it's likely Dante will win by majority vote, but the thing is, people fail to realise the one true deciding factor in this fight.
Dante is half human, meaning he will also have some human vulnerabilities, whereas Alucard is all vampire, the king of the species, but is hindered by none of the traditional vampire vulnerabilities.
I will say this though, if Dante could Trigger without weilding a Devil Arm, I may be inclined to give him more credit than I have been before, but so far, we've only seen him trigger while he's either near a Devil Arm, or weilding, at the very least, Rebellion.