I'll agree that Samahada is useless against senjutsu, forgot about that. Killer Bee isn't limited to regular kenjutsu as he can also use his lightning enhanced nature after realizing normal kenjutsu won't work. I don't know how SM would fair against lightning enhanced sword so I won't argue for either or in that case.
Killer Bee himself is durable since he's able to tank Ei's lariat. After one hit from frog fu (since he has no knowledge), Killer Bee will simply adjust. After getting the summonings out the way, Killer Bee can transform comfortably and use his whirlwind technique or TBB to overwhelm Naruto. I'm not Killer Bee stomps SM Naruto since no one probably can stomp him, but Killer Bee easily has the means to take out Naruto and counter his SM with a good mix or base mode, V1, V2, and full on Bijuu mode.