We have three different carriers and I love each for various reasons.
The blue above is a Hotslings sling. I ordered it last summer when we weren't sure if Ollie was a boy or a girl. I love how easy it is to get him in and out of this one - it's fast and I can do it easily while I'm wearing it. The down side is that it's recommended for babies over 8lbs. We went for a walk and I used it, but had to hold him while he was in it to be sure his airway was open. I think Hotslings went out of business, but you can still find the slings on several websites, just not through the company directly. I bought one of the AP slings - 'adjustable pouch' - and it fits pretty good. It's a little low for my preference, but it's not bad and still comfortable.
We also have a Moby. It is SO comfortable!! The same day as above, we walked again. It was a little windy so that walk didn't last as long, but Ollie was oh so cozy in the Moby. Again, this one is recommended for babies at least 8lbs for the same reason, so I was conscious of his neck the entire time. I liked it better though because it was easier to see him and I could adjust his height in it. The only down side that I've found with the Moby is that it's so loooooong that it's difficult to put on in a parking lot or other place where the floor or ground isn't clean. There must be a trick to figure that out. We ran errands last weekend and I tied it on before we left and just wore it in the car until I needed to get him in/out of it. It worked well, but that would be really hot in the summer.
The last carrier we have is the Beco. Hands down, my favorite. A friend who had her baby just two weeks before me recommended it. I'd planned to get an Ergo, but because I couldn't use the ones above, I needed the carrier ASAP. I could get the Ergo locally, but not the infant insert - which I'd need to use it with Ollie. The Beco came with its insert - and had the same 2-day free shipping, so it was the one we went with. I absolutely love it! I've not mastered getting him out without taking the entire carrier off, but I love that he's comfortable, I'm comfortable and I don't have to worry about him being able to breathe like I did in the other ones.
At 17 days old, he's still not 8lbs yet and I really didn't want to wait to use the carrier. As often as he needs me to hold him, the Beco has been great for me so I can have use of BOTH hands!! Who knew that was such a luxury?! It's basically the same as the Ergo, just a little different with regard to the insert. He'll use the insert until he's 15lbs and then graduate to the regular 'seat' of the carrier. The only thing I've found that I don't like too much about the Beco is the fabric I chose. Apparently the organic cottons aren't color locked so even with washing, they say the dye can come off on light clothing. I'm wearing it today with a white shirt, so it's the test! Hopefully it won't bleed brown all over me, but if it does, I'm wearing a size large maternity shirt that I only wear around the house these days so it won't be a big deal.