Bjorn does make some ergonomic carriers now that are just fine and comfortable, from what I hear. The old school Bjorns don't stay comfy for anyone.
If you have a Babywearing Internatinoal group near you, go to a meeting! They're so helpful.
Carrier preferences are so personal. They're like shoes or bras, just because it's high quality doesn't mean it's a good fit for you. Personally, I liked a ring sling for the first few months, and I like that I can still use it for quick ups and downs now that he's older. Most SSCs (the ones with buckles, like Ergos) are awkward with newborns and require a special insert, but some can be adjusted for tiny babies. I know Lillebaby is one, but there are others. I prefer a SSC now that my son is bigger (mine is a Lenny Lamb), but I'm considering a wrap conversion mei tai for back carries. It's all very overwhelming at first, but read up some, go to a couple BWI meetings, and you'll get there.