B.B.
http://betterbabywearing.blogspot.com/2010/03/babyweaing-...
Here's a great blog about the different types of carriers. I have heard great things about Ergo (a friends has one and loves it). I have a Kozy Mei Tai and a Girasol woven wrap. The woven wrap is very versatile and can be used many different ways, including a "ring" sling (you tie a slip not), front, back, and hip carries. It is possible to BF in these carriers and the ones you mentioned, but I prefer not to. I know many BF successfully in them, though (my friend BF's her 1 y/o in the Ergo while shopping and nobody can even tell).
Just avoid the "bag" style slings that were recalled.