I've been spamming how underrated Aspen is for almost any class, in that he's one of the best pets to bring to bossing (for a party of 3 and above.)

Happiness: 10INT 10% Crit and 3 Health Regen -> very decent for Sorc.
Arcane: 15% damage for 4 seconds for all party members -> THIS.
Passive: A single-target knockdown (stun) with high damage and 10% armor reduction (100% of the time). -> Another party buff.

One thing about Ribbit: If someone else stands on top of your frog, HE gets the crit bonus, not you. Ribbit being a ranged pet can be a pain to position for your use during bossing, so it really isn't as splendid a pet as it is in theory.