Hi T.!
I am a mother of a 6 yo girl and an 18 month old boy. I've tried a ring sling, a bjorn, an ergo carrier, and a mei tai. I think each one has its purpose and can be so helpful but for me, the ring sling is by far the most versatile and the best for shopping, errands, stuffing in your diaper bag, family reunions etc. It does take a bit of a learning curve to figure it out but once you do, I think you'll really enjoy the different positions you can try. My girl loved the kangaroo position, my boy always faced in to my chest and now enjoys straddling my hip. A web page that might help in your decision and has a great how to section - http://www.thebabywearer.com/
With the ring sling, one of my favorite things is once a child falls asleep in it, it is actually pretty easy to transfer them to their bed, the car seat etc. And in reverse, you can pick up a sleeping baby from a car seat, hold them close, through the sling around you and wa-la you are cuddling your sleeping baby while still having your hands free! You can find them cheap, make them yourself (thats what I did), or find some ones so fancy that they are art pieces.
Have fun!
K.