When my oldest was a baby we had a Britax car seat given to us, actually two different models of Britax were provided from a family who no longer needed theirs. Having a well built car seat helps ensure that you feel safe with your child riding in your car or a family members car. The only downfall I had, as a parent who shared custody was that we had to transfer the car seat back and forth. This became no problem later on as a child car seat was purchased for both vehicles; his and mine.
There are so many brands of car seats that a first time parent may have difficulties in choosing the best one for them that is also within their budget allowance. A five point harness is on, I believe, all car seats at this time in life but beyond that you want to ensure that your child’s car seat is comfortable as well as supportive for them. Having a comfortable & supportive car seat will make a world of difference for those long trips in the vehicle with the kids.
I personally prefer the Britax brand because I had such great success with this brand of car seat, the car seats lasted ages and could even be used for my son who was born four years after my first child. These car seats made by Britax held up through three children without much issue, I can not say the same for other brands I have seen people purchase and use with their children.