We've tried a Sakura Bloom ring sling, the Ergo Sport, and a homemade carrier that's sort of like a mei tai or SSC.
-I CANNOT get the ring sling to work in any way that seems comfortable and secure for Baby Bird. The fabric seems to slide through the rings, so it doesn't stay tight, and I can't get him in it in a way that gives him decent head support without seeming to smother him. I was so excited for this sling - I thought it would be easy in and out, but it isn't. Luckily, I rented it, so I will be returning it this weekend.
-Baby Bird really likes the homemade carrier, but since his head isn't above the top of it, and his neck gets bent a lot, and it seems like he could fall out the side, I'm not sure it's safe and I've vetoed using it, even though both dh and Baby Bird like it. My mom says I must be doing something wrong, since she used this type of carrier with her itty-bitty babies, but we haven't had a chance for her to check out that theory yet. Maybe next week.
-The Ergo is a decent but not perfect option, and we haven't used it much yet. We don't have the infant insert, because we tried it out, and it seems like Baby Bird doesn't really need it. (He was 22" tall at birth, so that may be part of it.) Plus it seems obscenely hot for using in Houston at this time of year. It's somewhat quick, and somewhat easy to use, but not as quick/easy as I would hope. I will say I think it will get faster with time, and be easier once he is bigger. It is fairly warm even without the insert, especially considering how warm Baby Bird and I are all by ourselves! We don't use it a lot because it is hot and kind of cumbersome, but I expect it will get more use as the weather cools down and he gets bigger. dh also likes this one.
I have to say - I have not found a babywearing solution that meets with my expectations/needs at this point, and that is frustrating!