initially I was choosing between the frontier 90 and graco Argos 70. A ended up going and they didn't have the frontier 90 fabric I wanted. Recently I came across the sunshine kids radian xtsl. I knw it's a narrow seat mainly for 3 across but is the slim seat a problem when your trying to harness older kids.? I also know it's the only seat with steel base or frame one of the two. A from what I've seen online it's the safest seat. Any pros or cons.?