Trikes are a great harvesting mount for berries and thatch. They also have good attacks (which do knockback to smaller dinos.) My favorite attack is the charge attack. I use it to raid wood/thatch bases. Overall great mount!
I can not stress enough to my friends how useful the trike is. Early game it makes a great pack animal. Late game in groups of three or four it can be used as a decent battle mount. Taming a trike early on can be a great way to start a large base and keep you well fed with berries.
A triceratops is a very special dinosaur in this game. It is easy enough to tame at a low level, yet powerful enough to take on raptors that could kill you easily. It can collect enough berries that you would never go hungry again, and still have some berries leftover to help tame more trikes. They are very slow but it can make up for it if you increase the weight, attack, and stamina stats. It is an extremely good pack animal because it can carry a lot, but still defend itself, especially if it is in a large group. Overall, the triceratops is one of my favorite and most versatile dinosaurs.