I have both. DH would wear the ABA one, but not the HAB. So the ABA tended to be the "car" sling. It lived in the car and we used it when out shopping. I also found it handy for those times when I needed to only have her in the sling for short periods, but often.

The only thing I found with the ABA one was that is rubbed under the back of her head, but that could be due to me doing something wrong. Will see what happens with the next bub.