While I have not seen the Elevation, I have been around quite a few Proof customs. I have handloaded for three, a 300 RUM Terminus and two 6.5 Creedmoor's one a Terminus the other a Tac II. Been around another five that I have seen fired at the range. ALL were superior rifles in every aspect I could see for a custom. The three I loaded also cleaned up easily.
Most recently a friend brought a 6.5 Creedmoor and a 6.5 PRC to the range and shot Hornady ammo. Both were fantastic shooters. I shot the 6.5 PRC for a few rounds, fun to shoot something new.
I would not hesitate to buy any of their customs, never saw one that had any sort of issue.