So, my ds is approaching 30 lbs at 9 months, and not mobile yet really. He is very attached and I have to wear him a lot. I am starting to be in some major pain, and my sciatica started up again yesterday so painfully that I keep yelping and dh runs in concerned. We had a front criss-cross sling that was a little too stretchy and he slid down too much, so that's out. The bjorn, well, you all know the problems with that, but I did like the criss-cross design for my narrow shoulders. Maya Wrap ring sling, love it, beautiful and easy, but it is hard on my shoulder and back at his weight. Evenflo Vibra on the back, great in a lot of ways but the straps seem to slide off my shoulders some, and the belt sits on the waist, not hips, where I really need it to translate the weight. Tried an Ergo on once but he doesn't like to face in, although I didn't try it on the back. I am very slight, narrow frame. Tell me what worked for you!