Compared to the contemporary military bolt action rifles of the two wars, Mosin Nagant, K98 and M1903, it has the smoothest action (=high rate of fire) and the largest magazine (10 round as opposed to 5 for the others.). It is technically not as secure at the mauser-pattern locks, but it's practically unnoticeable.
The K98 is good allround, having all the qualities a rifle need. An excellent firearm.
The Mosin Nagant it exactly what the Soviet Union needed: A cheap, functional rifle that didn't have any serious drawbacks. Kinda like the AK.
The M1903 is made on the same type of lock as the K98, a mauser pattern lock. Furthermore, the M1903 is known to be exceedingly accurate.
The discovery show seems to be focusing on innovation and service life in addition the effectiveness, handling, and accuracy. It is not comparing the rifles to each other, lest the newest firearms automatically get the top place. Just don't trust the facts too much, the show is very impressionistic.