I love my Ergo for newborns!!! I've used it for 3 newborns now and it is excellent. I did try a moby wrap for my 4th and it was too much work to get the thing on. You can get an insert for the Ergo, BUT, honestly I've used it without the insert too - you just have to make sure you have the carrier on tight and put the baby in a sling like position or with their legs tucked up underneath them. Super easy to get on and off. I have used my Ergo almost daily since my 3rd dd was born, so close to 5 years now. I love it!
ETA: oh and I tried slings a few times too, and no matter what kind I tried, I always hated them!
I can't wait to use my newbie with my new ergo. I didn't have it with DD. I did use my sized sling with DD and I found it useful in some situations. It was fast to get on and get her in...and it was small and compact to store in the diaper bag. Two pluses. I only really used it when she was tiny though.