He's undoubtedly the best known Russian singer outside Russia/Soviet Union.
I suppose that the vast majority of non-Russian/non-Soviets would be able
to name only him if asked about a Russian singer (and of either gender at
that, I'm sure).

Nonetheless, I think that Mark Reizen left any bass or bass-baritone
far behind and in the dust.  Shalyapin's Boris is nowhere even close to
Reizen's.  Reizen had the power and majesty that Shalyapin didn't have, not
to that extent.  The scene of Boris's death in the 1948 recording (reissued
on Lyrita or Lyrica) must be the best ever; the moment when Boris tries to
rise once more and sings "Ya tsar yeshchyo!" is absolutely blood-curdling.
I compared it once with Shalyapin's, and it's just not quite it.

Reizen's very voice was an astonishing phenomenon: incredibly powerful and
yet almost tangibly soft.  This is particularly beautifully shown in such
arias as that of the Vareg Merchant's (whatever he's called) from "Sadko"
or Gremin's in "Onyegin".

I guess I digressed from your question.  I just think that all in all,
Shalyapin was a bit overrated.  To think that he was so famous in Europe,
while Reizen remained practically unknown - this is a bit beyond my
comprehension.

-Margaret Mikulska