I have used:
2 slings--hated both;
2 Infantino front carriers--way too flimsy for me to ever use with confidence;
a Sleepy Wrap--great for winter time or around the house, and especially snuggly for newborns--and good for grocery shopping when I could just tuck the baby away from the well-meaning but dirty hands of fellow shoppers. TERRIBLE for days when it is over about 78'.
this week I received my ERGObaby Sport trial (I got mine from www.heavenlyhold.com ) I LOVE this new carrier, am keeping it, and will probably never use another again. SOOO comfy, easy to put on, and my baby loves it too! (and it has a sunshade to put over the head).