I have seen discussions here lately about disappointing discs, or the best from each company, but not one where you got a disc and were surprised at how well it worked.
I have to say for me it is a Champion Viking 172 gr. I only got this disc after getting a 35$ voucher for winning a tourney. He had mostly Innova, I throw mostly Discraft. He didn't have any Innova I was familiar with except heavy Valkyries. I picked up a Viking and asked him how it was to a Valkyrie. He said just a little more stable. I picked it up, hoping it might find a way into my bag, if not it had a cool stamp and might make a great memento of the tourney tyo hang on the wall.
The disc ROCKs! I love it. It is super straight and did not have any tendency to turn over with full power. I was getting as good distance with it as I ever did with a Valk, and just shy of my record distance with a QJLS. The disc was a big surprise and found its way into my bag immediately where I need distance on straight shots. Distance is still improving with it and it may become my go to disc for max distance( currently held by my ESP Crush).