I have used a fair few slings/carriers.
Ring slings: great for around the house and as a 'just in case' when out and about with two littlies but only one buggy. Minuses: you tend to need to use one hand to support a lot of the time.
Wilkinet: people love them, I hated mine and gave it away at the earliest opportunity. Baby origami with loads of fiddly ties and straps and unnecessary padding.
Baby Björn: I found mine surprisingly comfy and easy to use and if you are putting it on properly, the weight is pretty evenly spread. DS1 liked it best of all. I think there is a lot of snobbishness around slings v. carriers but if it works for you, go for it. The carrier I'd really like to try is the Bushbaby front carrier for little babies (also fancy one of their toddler Elite back carriers).
Moby Wrap: divine, spreads the weight beautifully in voluminous folds of fabric. Don't be put off by having to 'tie' it on, it is surprisingly easy.
Papoozle: similar to a wrap but with a click on waist band so easier to use for those who are afraid of having to do baby origami. Also spreads the weight beautifully. Slight downside is that you need a separate 'belly band' to support a tiny baby. But at the moment it is in joint first place with the Moby for favourite status.
Toddler Patapum: only really used with my sling refusenik DS2 who didn't really get on with any sling. It was practical and did the job when out and about with a sleeping toddler. Or two sleeping LOs and only one buggy. When DS2 was bigger I found it easier to use than a ring sling.
Phew! I'm slinged out now!