[CQ-Contest] CW or SSB FCC says neither.

[Rich Gelber, K2WR]

Another aspect of both CW and SSB is that a sufficiently skilled operator
can copy more than one signal at a time.  I'm not aware of a "new digital
mode" that supports this "feature".

Of course if you increased the data rate, and hence the bandwidth, you could
make the QSO's so fast that it would be indistinguishable from copying more
than one signal at a time, but the increased bandwidth would leave CW as
superior again. ;-)

Rich, K2WR