The absolute best--insert whatever turns you on,the truth is it's only the absolute best to the fellow who says it is, in his system and with his ears.
In my system it may not be, and over the years I've had several well known phono stages from Atmasphere, CJ,Levinson,Audible Illusions,Sutherland PHD,to name a few,and most recently I'm happy with the Steelhead.
But which one was/is the best?
I can't say, never had them in the same system or at the same time to compare them,but I can say that each one was the best, at that time to my ears in my system.
I can change my opinion on how my phono stage sounds when I listen thru headphones,-the K702 are clean fast and a bit toppy, the Grados are a bit rounder, slower and more middy.
So if I only had the Grados I would say that my phono stage is warm, great in the mid range and the best ever, if I liked middy warm sound.
I think phono stages are no different than anything else.
If you are serious, try more than just one and definitely compare them in your system.
Only then will you know which phono stage is the best.
As I said, I couldn't say which of the phono stages I've owned was the best, but they were all very good.