i've owned or had in my system a few good phono stages including the Aesthetix Io, Io Sig w/dual power supplies, the Lamm LP2 Delux, BAT VK10SE and Blowtorch. i've heard the Connoisseur Definitions 4.0, Boulder, Manley, Wavac, and others at shows.
the phono stage in the battery powered darTZeel NHB-18NS preamp that i am currently using must be considered as a contender as best phono stage. it's extremely low noise floor, other-worldly dynamics, and ease and naturalness make it the best phono stage i have heard.
some of the phono stages i have only heard at shows may be as good or better but nothing i have experienced would indicate that.