I think that a lot of people buy carriers, such as Baby Bjorn and Infantino, simply because the name is recognizable and they can be found in nearly every store. Unfortunately, though, it seems as if people don't pay attention or really care about the differences of front facing versus rear facing.
I own an Ergo baby - after having owned 4 others! I LOVE it ... and so have both of my kids!
Here is a great article I found today by The Eco Friendly Family that I believe that every mother should read!