The Sabertooth can collect meat about as well as Carnos can, and are about as strong, but in addition, along with dire wolves, they collect hide, chitin, keratin, and other non-meat materials from creatures at a high rate. Leech blood, for example.
Powerful, decent stars all around, fast, and can leap forward, allowing you to cross rivers and gaps without even entering them.
Small attack range. Often times leeches will attach before your mounted saber's attack connects.
This is basically an upgraded raptor. You can use them to collect meat, travel, and cave exploration. They're great for taming other dinos. Bring them along when you tame other dinosaurs so you can easily kill anything that tries to attack you or your taming dino.
It is a very fast mount, especially when you sprint + jump. It is stronger than a raptor, weaker than a carno(in the wild). Tamed if you level it up enough it can even take on a rex. It harvests a lot of chitin and hide, even more than it harvests meat. Perfect creature to cave with.