Honestly it's only great for babies 5kg below. No great support for babies above that so you'll definitely have bad aches. I sold mine off after 3 mths of using it. But it's food cos baby will fall to sleep once in the carrier.
But if you were to buy it, get 1 size bigger, also go for the summer version which is mesh material although will still sweat when using it. My size was L but I bought XL instead.