Most clipper brands make clippers for animals aswell as humans, so I'm speaking from expirence with my horse. I prefer Oster or Wahl. Both brands have held up well for me.
I can't speak for human clippers because the only pair that i've expirenced are the pair that came in my student kit and they are Wahls, but the cheapest ones that you can get and they haven't held up as well.
Andis has a pair that (from what i've heard) are really nice. The ones that are all silver.
I guess i'd say the more you spend, the better quality you get.
Good luck!