Infant car seat or 4 in 1

Have you guys gotten the car seat? If so what brand and why? And is it an infant seat or the 4 in 1? Im currently looking but i have noooo idea on what im looking at. Ive heard people say the infant one is more convenient because you can carry it. But if you get  the 4 in 1 you dont have to purchase another one down the road. Any thoughts?