Ok, points in favor of Booker
1) He's technically Human, the only thing Alucard goes easy on and will allow to kill him.
2) He has a varity of Vigors and Gear which sets him above and beyond the normal humans Alucard normally faces. Perhaps setting him on par with Anderson, another Human who Alucard would have let kill him.
3) Alucard will probably never release his seals fighting him, not even if he needed to, to survive.
Points in favor of Alucard
1) Technically 1,000,000 "extra lives" counting the souls he has within his body that he uses to tank deaths.
2) Already Massive regeneration
3) Extremely high physical strength and speed, with enhanced senses and athletics
4) The ability to phase though walls
5) The ability to walk on walls/ceilings regardless of gravity
6) Various other low level powers such as telekinesis, hypnosis and the like associated with vampires
7) Two oversized handguns and a cool trenchcoat and hat.
Also, Street Level Alucard is not...