I’d personally go Arri (or that Aaton – very nice!) as more people know the camera so if there is an issue, you’ll get it fixed easier and will have a bigger support community in general. The SR1 has always been FAR from quiet in my experience though.
Personally, I never felt a need to have a camera – it’s the film costs that kept it out of my reach. $5k could probably get me 10 weekends with an SR3 body in the Nashville area as houses will basically give them away.
If you’re going to be renting lenses (with S16, I’d want something sharper than Super Speeds as well), might as well rent the body.