You can absolutely carry your newborn tummy to tummy in a pouch style sling. I have one from kangarookorner.com and it is the best one I have tried, and I have several different slings/carriers. The link I mentioned has good pictures of how to accomplish this. What I would suggest is that you get used to carrying in a pouch, and just using that before you attempt the ring sling. I think most ring slings work about the same...now there are definately some better than others, but generally speaking they operate the same way. My lightly padded "boutique" sling from Kangaroo korner is my very favorite. The padding is light for comfort, but not too bulky that it gets suck in the rings, and the shoulder pad is just right. Be careful buying one with too bulky of a shoulder pad, or no padding. I have 6 ring slings, a few I don't like at all, but my fav is the Kangaroo Korner ones.
I think user friendly wise, your pouch is your best bet. I would give that some time to get use to. I don't know what kind of pouch you have, but mine have several rows of snaps so it can be adjusted. With a newborn who doesn't weigh much, you won't have the problem of him/her weighing the pouch down. That is when I think the rings come in handy. Like my 9 month old is 24 pounds/30 inches so by now he weighs the pouch down too much. Anyhow, good luck with the new babe