I like the one without the head supporter, I think it is the sport. I just think the extra piece of fabric should be removable, since you use it for more time 'after the baby can hold their own head up' and you have to "tuck it" into the pocket. My friend has the performance one, it feels very comfortable. I plan to get one for me, but I might get the sport so my husband will use it too.
Re: Ergo
did you see this?
https://kb.ergobabycarrier.com/questions/42/What+is+the+difference+between+the+ERGObaby+Sport+Carrier+and+the+Performance+Carrier%3F
here:
https://www.carrymeaway.com/pages/ERGOComparison.html