General

Jaira does give you +20 speed and jump while Snow White gives none and 50% stance. Most players have enough speed and jump from equipment that it doesn't matter which jaguar you choose. Jaguar Rider + Jaguar Boost + 4 rings will get you up to the cap easily. Since all jaguars are easy to cap speed with, Jaira's bonus is largely useless and you should pick a different one.

@heyitsjustin both Jaira and Snow White max my speed/jump

Jaira and Snow White both give max speed and jump. If not for the stance on Snow White, I would use Jaria. xD

Jaira was available before Snow White was haha

Unless something's recently changed, Jaira (the black one) is a lot more common than Snow White (the white one).