I have used a number of slings with both my bubs and both were big babies.

Ring sling
padded shoulder mesh fabric
Put a lot of weight on one shoulder, by 6mths too heavy to use for long periods. Mesh was slightly cooler but left a grid all over bubs skin. Took a little to get used to but easy to use, easy on and off. limited positions and always worried about cutting off circulation to bubs legs or squashing them

Backpack
quite large and bulky but they have better ones now. At the time only suitable from 6mth. Good storage underneath but hard to get on and off without tipping bub over. Great for active outdoors hiking, sports at festivals/carnivals. worked until 18mths

HAB
Love it, stretchy jersey fabric makes it very cuddly but very hot, could only wear it with aircon on. We tie it on before going out and pop bub in and out.

Wrap
We made our own wrap (same as HAB) out of lighter cotton and are trying out muslin at the moment and it isn't as stretchy but is much cooler. Check out mamatoto dot org for some great instructions on wearing in different positions. Our DD is over 8kg and we still carry her in the newborn (HAB style) but are starting to experiment with hip carry and forward facing. My hubby loves this one too - took him 2 goes to learn how to tie it - he loves all the attention he gets from the women I think

Have fun deciding