First of all, if a storeperson said that she thinks that Bjorn is 'the best', especially if she sells other carriers like Ergos, then I am inclined to think that she is thinking only of her profit margin!! There are many reasons why Bjorn are not the best, but the two clinchers are comfort for baby (they are supported by the crotch whereas an Ergo supports them in a sitting position), and comfort for Mum. Few can wear a baby in a Bjorn past 8kg, I could not use mine after about 6 weeks!!

I am one of those who did not find the Ergo comfortable compared to my other two shouldered carriers. That is to say, it was not actually uncomfortable, just not as comfortable. I could not use it for long carries - ie: upwards of three or four hours - as I can with other carriers. I also own a mei tai, a woven wrap and a Connecta (mei tai style SSC). I am about 5.7, but narrow in the shoulders, and I found that the Ergo's padding was too bulky for my preference. If you've tried it on, you would have a pretty good idea of how it works for you, but it is preferable to try it for longer if you can.

Yes, they do become second nature to put on. There are different ways to get bubs onto your back for back carries, with the hip scoot being the easiest with an Ergo (IMO) (google it - there are youtube videos). Unless you are like me and have a bub who can't hang on or wriggles a lot, then it is safer to put the carrier on a chair/couch, sit bub on it, then sit in front of them and do up the waist band, then lift them up. But with other methods it's good to practice with a spotter or over a bed, then once confident you won't need the spotter. It is easier with a cooperative toddler or baby though.

You can buy an infant insert which can be used from newborn to four months.

Another good carrier that has a mei tai stylre waist band, cinches in for newborn or outward facing carries and can be worn up to 20kg is the Pikkolo.

HTH!!