I won this debate in the previous tourney, Gaara wins this.
Although I think Yamata no jutsu was restricted, that could give Orochimaru the upper hand, Gaara's flight will give him the advantage, Orochimaru barely has anything he can do against a flying opponent apart from Yamata no jutsu, while Gaara has access to sand in the ground ( as we saw when he fought Kimimaro ), he could rip Orochimaru apart and seal him under the earth to keep him at bay, although this isn't a definitive win for Gaara since Orochimaru can hardly be killed...
I'll still give this to Gaara, high diff :scorps: