Travel system or separate car seat?

Ella

My dad works fitting car seats and has lots of training on them so I've asked him and he's said as long as the travel system is a brand that also sells separate car seats then they will be the safest.

So do I buy a car seat separate from the pram which I know will be safe and get a slightly cheaper pram? Or do I go with a more expensive travel system with a reliable car seat?