With what you said Id got the convertible way..less hassle of having an extra seat on hand.

I am one that Loves to leave baby in seat and be able to carry him around, transport etc without waking. We have our seat in the box still. I feel bad even DH is like WHY? LOL I have 2 convertible carseats for infants to child..and I love them both. Never did use as infants..