I have no personal experience with Proof. I can tell you that my GAP-10 has a Bartlein and I think it’s fantastic. My A.I. Has a Brux barrel from Accurate Ordnance, and it is also a fantastic barrel. Once you get to the top end, I think they are all very similar. May just depend on what your smith has spun up. Maybe he has a certain brand he likes working with. That may be your deciding factor.
I am upgrading my rifle with a proof research it is a savage. I don't have it yet so I cannot give an opinion other than everything I hear about proof is good so I spent the money there myself.
PVA Cut Rifled Ruger RPR Prefit. Josh uses Rock Creek cut rifled barrels. When we talk about Rock, Bartlein, Kreiger, Hawk Hill, Mullerworks, etc. etc. they all shoot the same for me and I have them all.