Hugo is popular with the Attack based clans especially
Montana (the 6 attack gets them above the 8 attack minimum) and it creates a larger attack gap meaning you can 0 pill every round the the opponent will have to spend generally atleast two pills each round to get above the attack gap.
Eyrik is more associated with the Power clans as he makes the power gap bigger. If you use
Nanook with bonus and
Eyrik with about 4 pills she will 9 times out of 10 dominate 5-6 pilled cards because with 10 power and - 1 power on the opponent she is nearly unstoppable.
Hugo suits people who like to pill 1-4 most rounds.
Eyrik is more of a Nuke card where you pill 5-7 on certain rounds. With this being said I have used
Eyrik to pill only a little every round and vice versa for
Hugo. It depends on your play style. But when it comes to low pill battles
Hugo obviously works better, when it comes to high pill battles
Eyrik obviously works better. I prefer
Eyrik personally but both are wonderful cards and the only way to find which suits you more is to try both of them out.