So I've been really looking into infant seats, ready to order at this point. I'm just stuck between the Britax B Safe 35 or the Chicco Keyfit 30? I have an almost three year old and we used a Baby Trend Expedition travel system with her. We are very active and I have the sit and stand ultra as well. I'm trying to accomadate many things - small, light, easy installation, high safety ratings, sit and stand compatible. What do you ladies think?