First the positive - the BabyBjorn is very easy to use and can quickly be put on and taken off unaided. I found it much easier than wraps, but maybe that's just me.
But the negative - after a few weeks my baby was too heavy to carry for more than about 15 minutes at a time. OK if wanted to hang the washing on the line, but not for much else. All the weight is placed on your shoulders rather than your hips, making it uncomfortable to use. Another important point that I was unaware of at first is that it's a "crotch-dangler" type carrier, which isn't great for babies, apparently. Google "sling guide" for more information. I would recommend buying a soft structured carrier instead - Ergo, Patapum, Beco, Manduca, for example. They are a similar price, easy to use and more comfortable for both parent and baby.