I'd like to see Gregerson brought over here - the guy has been one of the most consistent late inning relievers in baseball. Whether they make him the closer or setup man, he'll be valuable. Likely will require a 3 year deal I'd say.
As for Robertson, I'm not sure I'd sign him for 4-5 years over $40 million. I mean the thought of him having a season like BJ Ryan's 2006 season definitely is tempting; however he could also blowout his elbow in the next year or two and barely pitch. Handing out big deals to relievers is risky. I'd rather let Brett Cecil have a shot in the closers role - though that means if he has success, he'll be way more expensive in 2016.