Hopefully one of the gurus will see this and reply, but I thought I'd add my 2c.

The benefit is you get two hands free to do other stuff!

I have a baby bjorn and we (well DH) has used it with both the kids. He loved that it was easy on easy off. Truth is, they aren't great for the baby's spine or your own.
I used a neitei and a peanut style sling with NB and I loved both for different reasons. THe peanut was easy on easy off for me, but many bubs don't like the position they're put in in them and often they are sized (a ring sling is similar but multi sized) so unless you and DH are the same proportions it will only fit one of you. We loved it and only stopped using ours recently - DS is 18months old. he's finally got a bit too heavy for my shoulder.
We also loved the meitei for longer carries and back carries when he got older (although we used the peanut for back carries too). I have also carried my 20kg four year old in it too not so long ago, so quite versatile. It does have long fiddly straps which are a bit of a pain while you're learning but it fits all sizes.
Both can be exxie, but I made my own. The peanut cost me $4 - no joke I got some duck cloth on a great sale and I have enough left to make another should my heart so desire.
The meitei I bought 100% linen for for strength but also got a bargain so it only cost me $25.

Recently I have splashed out on a BabyHawk OhSnap - it is better support for my bigger kids.