Sorokin > Soderstrom, but no Isles fans really watch either (including myself).
And that debate simply comes down to their numbers. Sorokin has simply had better numbers over a larger sample size than Soderstrom. And I think most feel like that two years in the KHL is more difficult competition than one year in the Allsvenskan and one in the SHL.
I think Soderstrom plays a less erratic style than Sorokin, however. If I were to compare their styles to the two current NYI goalies, I would say Soderstrom = Griess, and Sorokin = Halak, but at the end of the day, nobody really knows how they will pan out and we don't waste much energy debating between the two.