I Googled the Ergo and just from appearances it doesn't seem to have as good support as the new BB I just mentioned. However I guess it's designed to wear on your back as well. The straps look a bit unpadded for my liking though.

We have two baby carriers, a Pixie sling that's kinda like the new BB but not quite as sophisticated and a proper structured backpack style carrier (can't think of the brand off the top of my head). Both have nice thick straps but the backback more so, and a stomach belt with lower back support. Actually it's pictured in my photo in the gallery entitled "The Kids" with my youngest in it. It's really good also as it has an aluminium stand that you can use to prop the whole thing on the ground with baby still in it. We have used this to feed our 1yo whilst on picnics and to keep him in one place when it's not safe to roam around. Anyhow I should go and see what brand it is...