Wow! You're one tough mama! My Bjorn hurt my back amost right off the bat so I did Right slings, Mei Tais, then wraps. Although I have no experience with an Ergo, I know lots of ladies who LOVE them. And I think you'll be pleasantly surprised when you get something other than your Bjorn. You'll totally understand what the fuss is about!
I love my Mei Tais (MT). They are incredibly comfortable because your child is pulled toward you, close to your center of gravity. Babies become almost weightless, if you can believe it! Toddlers, too! I've worn my 3 yo for a time (he's 30#) and it's comfortable! But I wouldn't do it for long, not with him. Of course, not every MT is built the same, and there is a degree of personal preference involved, but for the most part, the major brands our there fit the bill nicely.
One of the things that can be daunting about a MT is the straps. They are long and can drag on the ground when you are first putting the carrier on. But aside from that, they are great with so many wonderful styles and prints to choose from! That's what I enjoy about MTs (besides the comfort), is the style. And it's the reason I won't choose an Ergo--too ugly in my opinion!
But that shouldn't stop you from getting one! It is very mainstream looking and suits its purpose comfortably.
That said, I would encourage you to get a FreeHand if you love the looks of them. The resale value is wonderful if you find it doesn't agree with you, but I think you will be a quick convert and really, really wish you had discovered it sooner!
Good luck to you!
Kristin