Gaara should win although that blast of Juugo would be pretty deadly. The thing is, Juugo can't spam it and he can only use it in CS2 and has only used it once. Juugo also loses control of his actions in CS2 which Gaara can take advantage of and sand coffin him while Juugo is on a rampage. Juugo does have thick skin so it would be tough for Gaara to completely put him down though but a sand tsunami should suffice. I'd very much like to know how fast Juugo is compared to Kimimaro, part 1 Lee and part 1 Sasuke though to see whether he can overrun Gaara's sand defence or not.
Gaara wins with mid-high difficulty IMO.