The Sonica has gotten xlnt reviews and is 17 years newer in design. You can run everything thru your tube pre (I do and have the Mk II of yours).
But... I think you really better listen to both if you want to be sure.
Or get the Sonica and then start thinking about what might be a lot better (maybe Benchmark, Yggy for Redbook only, etc.)
The rate of evolution in DACs is very high relative to every other component.
You will also want to determine what's the best test music to use...
and... Tidal is undergoing some changes right now
But... I think you really better listen to both if you want to be sure.
Or get the Sonica and then start thinking about what might be a lot better (maybe Benchmark, Yggy for Redbook only, etc.)
The rate of evolution in DACs is very high relative to every other component.
You will also want to determine what's the best test music to use...
and... Tidal is undergoing some changes right now