I haven't used the k'tan but I just wanted to say we loved our moby. It was the best baby related buy I made.
LO took most of her naps in there for months and I still put her in there on occasion at 8.5 months/24lbs. I couldn't recommend a moby enough, especially if you have a tough to get to sleep type of baby
I loved the moby but i have only just googled the baby k'tan and that seems pretty awesome. The only issue I would see is if you and your hubby are different sizes, it could not be shared. The moby is one size fits all.