Benefit of a tail:
In ring slings, you can adjust the ring sling to get the perfect fit! Or, multiple babywearers can use the same carrier.
Tail comes in handy when using as sun protection or when baby is sleeping and you want to give her privacy.
I also use it as a quick leash, loop it around my toddler, cinch it up, and I have a pretty little baby harness, lol! That way she can't dart too fast away from me.
Pouches:
I still use pouches for my almost 3 year old, and that's my carrier of choice in the airport. But I do like the sling for its versatility. :)
Sizing:
I'd use the Hotslings sizing chart and go from there. If you do end up with a size too big or too small, we can help you trouble-shoot and offer free exchanges. I'd give most focus on the measurement from shoulder to opposite hip and bra size, upper body size... All pouches have different sizing too. Let us know if you need more specific help, we've got the Live Chat, email, phone...