Being able to wipe out 25% of an opponent's life in one fell swoop could be a game-winner in the right circumstances.
I havent met them yet, but Ive heard reference to Halsin, Gut and Nine-Fingers Keene in conversations and in correspondence Ive happened upon
All the cards from a given set are printed on identical printers
Zinnia's primary ability, to get +X/+0 for each other creature you control with a base power of one is almost forgotten about with this ability, since you can make the most of your enter the battlefield effects and other strong effects to let you duplicate them
Some of the worst games of Cube you can play are the ones decided by protection from abilities, and those cards always get some special attention from me when I do my overviews of the digital Cubes
Putting a -1/-1 counter on a creature every turn is nice, too