Here's a good place to start researching:
I don't actually have a Maya Wrap, but (following the KellyMom links) I found a pattern and made a sling very similar to the Maya Wrap. I LOVE IT!!! It's very simple, very portable, very trim (no padding), and DD still fits at 13 months, 25 pounds - yep, she's a healthy BF babe!
If you don't sew, I say go for a Maya Wrap.