Dante has poweful regeneration too, but he has a good advantage. He's used to fighting demons and monsters like Alucard. So it would be interesting to see. ^^ The battle would probably go on forever. xD
That's true, I think Dante would win (albeit barely) due to Devil Trigger which can freeze time, increase his strength and agility and disrupt his enemies' attacks. Without that though, Alucard might win.
But if we add in Devil Trigger and Release Restrict, anything could happen between the two. Now depending on the level of the release restrict, is how well the fight would go. If its level 1, Dante may, MAY have a chance, because of Devil Trigger. If he uses Level 0, and become..well, Dracula, he may not be able to survive. So, depending on the level, is how well the fight would go.