Beco or Ergo baby carrier?

I need to get a new baby carrier. We used the Baby Bjorn with The Boy when he first came home. I loved carrying him that way, but it wasn't always very comfortable for my neck and back. When he got bigger I used the Hip Hammock (the original one - made by the original creator of it - before Playtex bought it). It was good too. But, that was almost four years ago and I know there have been improvements in carriers since then.

So, my wise readers. What do you guys think? Ergo? Beco? or Babyhawk which I just read about?

I want something Amazing Daddy can use as well, so it definitely needs to be easy on ones back.

Help!!