I LOVE slings. I've used them with all the kids and my daycare babies. I've never had one that didn't llove it. They're so easy to use and take everywhere, just be sure you have the baby in it properly. My fave are pouch slings. Ring slings are great too though. Some of the best on the market are Hotslings. They come in every color and pattern you can imagine!
http://www.hotslings.com
You can also find them on ebay for super cheap!