I got a Pikkolo because my baby wanted to face forward in a front carry position, and I had heard how bad it is for baby's spine and development in other carriers (like Baby Björn) where the baby's...
neat and compact, forward facing front carry safe positioning
hard to adjust straps for front carry
I got a Pikkolo because my baby wanted to face forward in a front carry position, and I had heard how bad it is for baby's spine and development in other carriers (like Baby Björn) where the baby's dangling from their crotch, whereas the Pikkolo can be cinched at the bottom and form a seat for baby facing forward. So this is one great use of it, however you need to stuff a towel in front of baby's chest in this position as it doesn't quite fit right. For regular front carries it's really form-fitting which I like. However, I find it nearly impossible to adjust the straps as they pull backwards and are on my back. The hip strap also has the buckles in an awkward inward position which makes it kind of unwieldy to buckle. I've only used it once for a back carry, but it seemed very well suited and comfortable.
My baby's a very big 5 month old (18 lbs) and in forward carries it does hurt my back. They sell a special belt to go with the Pikkolo for heavier babies and I think I may have to get one if I want to continue using this much longer, which I don't like. I also find the price ($129) too hefty. It doesn't seem as well-made and durable as the similarly priced Ergo. The reason I like this over the Ergo at times is because of its small size, which I find nicer for short walks. For a long trip out and about, it does start to hurt my back though.