Lets take a look.
Furret has a small 415 BST, small for even in-game. It's speed is decent (90) but Tarous has 110, as well as higher Attack. Furret does claim to more HP though, but is less bulky otherwise. So based on offensive and defensive stats Tauros takes it.
On Practicality, Furret does gain access to several field moves, such as cut surf and Strength. Tarous is less useful out on the field with just 2 HM's.
In terms of Movesets, Furret does gain useful moves like sucker punch and Me first naturally, but little else besides. This means you will have to spend more TM's on it to give it a chance on the battle field. Tauros learns a slightly better natural set with Thrash, payback and Zen Headbutt at it's disposal. 3 usable moves right there. Earthquake and stone edge just make life awesome for this guys in-game with the world of Max Potions.
So all-in-all, Furret isn't really that good. Tauros is what you want until you get snorlax post game.