I've been a fan since I first saw him in Cage Warriors (vs. Aron Jahnsen). I remember thinking "this guy could fight in the UFC" and that was at LW. I've never seen video of his loss to Sitenkov (who I'm also a fan of; check out his rolling kneebar sub of Neil Seery)
Both of his losses have come within the 1st minute by sub and I have confidence that he's shored up that part of his game training with Gunnar. While Sitenkov is hit or miss (mostly miss lately) at 15-12, Duffy has only lost once and that was his last fight in 2011. Would've liked to seen Cole get his shot but I think a composed Diego is a stiffer challenge but I'm fully on the bandwagon.
Talk is cheap...because supply exceeds demand.