I'm really addressing this at those of you who already have at least one child and primarily used a sling for the first 6 months.
For a range of reasons, I'm looking at not buying a buggy/pram for the first few months after baby's arrival (due mid-late November) and giving the sling a really decent try first - that leaves me free to buy a small-folding buggy at 6 months which will be cheaper than a full travel system and take up less space (therefore fit in my tiny car and narrow hallway). I am just going to pre-empt the sling-haters here by saying that I have already done my research and know that if I hate the sling (or if baby hates the sling) there are enough prams available online that I can pick one up quickly if I decide that's actually what we need.
So, those of you who used a sling a lot (and therefore had time to get used to it) - especially those of you who used one with a winter baby - what were the main advantages and disadvantages that you found with regularly using a sling? I'm not asking for disadvantages in order to be put off (As I think is clear, I've already decided what I want to do) but I'm asking so that I can be a little more prepared and have a full picture :-)