Sasori has a pretty massive arsenal. Iron Sand will be the biggest threat in this entire fight. I don't think Orochimaru has showed any feats that could do anything about Iron Sand? The only thing coming to my mind is if his Kusanagi can penetrate the iron, but I'm not sure on that one, and I don't think Orochimaru would do it so easily either.
You could argue Orochimaru has poison immunity due to the nature of his jutsus and (possibly) his experiments, but if he's not immune, then Sasori wins handily. One scratch is all it takes.
While Kabuto is strong, I don't think he'll be much of a factor in this fight. Most I can think of is him attempting to heal Orochimaru from any wounds if the Oro is indeed immune to poison. His Chakra Scalpels are nice and all, but Sasori fights from range. Kabuto won't really get close to use them.
Then, if somehow Orochimaru/Kabuto manage to beat Sasori's Kazekage puppet, he'll resort to the 100 Puppets. At this point, I highly doubt Orochimaru can do anything to win. Orochimaru probably knows of Sasori's heart (does he though?) so that's something, but it wouldn't matter too much; 100 puppets, fire and water release is just too much for him to handle. His last resort would be Eight Branches, but I still think the sheer number of Puppets, poison, Iron Sand and nature releases, as well as Sasori's own physiology would prove too much for Orochimaru to handle.
Sasori wins 8/10 times, 10/10 times if Orochimaru is not immune to poison.
I can't remember if this is only in the games, but there's a scene on Orochimaru's first encounter with the Akatsuki, and Orochimaru knew a majority of Sasori's techniques, to which Sasori retorted "You studied well" or something along those lines.
I'm not using this as a point for Orochimaru since I'm not sure if its confirmed or not, but it would explain why this rendezvous set-up was concocted by Orochimaru and Kabuto in the first place. Why would they plan this if they weren't too sure if they would win?