Don't own a Metis, but with Rogue upgrades there is a major improvement. The larger power supply and better caps really increase the dynamics. The upgrade makes the preamp sound smoother, less bright and more natural. Rogue preamps sound bright to my ears when using the stock components.
Since you are looking to upgrade, the Perseus is not much more money than the Metis Magnum and is a very neutral preamp with a wide soundstage. But it is very tube dependent.
Since you are looking to upgrade, the Perseus is not much more money than the Metis Magnum and is a very neutral preamp with a wide soundstage. But it is very tube dependent.