It was actually designed for use with newborns, and works best in high, snug carries. Personally, I'm wrap challenged... or rather, wrap annoyed. My apple-shaped body means that most wraps end up around my knees when I take the baby out, and I'm not patient with re-wrapping. So with the MB system I would put them on and then pop baby in and out all day long. I can do that now with a stretchy wrap, but still find that it gets in the way more *for me*. YMMV.
There are some "switcharoos" that you can do with the MB system that I never have managed with a wrap, that are more typical of ring slings... quick switches from front to back, for example, easy drops for nursing, that kind of thing. I do believe the new rings make them more adjustable--they're slightly larger and aluminum. But mostly I found that I could just grab tail and yank to get them adjusted--the stretch meant less fuss, so having it tighter in the rings didn't matter.
That said... with my current baby I rarely use the MB system. She is a low-tone back archer, and the combination sent me scrambling for mei tais for more security and resistantance to arching. The MB system works better with babies who like to snuggle, tend to prefer the upright position and for mamas who change positions a lot. My foster son was in prototypes *all the time* from birth, usually either tummy-to-tummy on my chest or high on my shoulder.
As a single sling, it's better for people who have "texture issues" with homespun type fabrics. The interlock is super soft, the shoulder has no pressure points but spreads a lot. Not my first choice for ginormous 10 month olds, but near the top of the list for newborns and small babies, and works quite well for older hip sitters who do some of the work for you and don't just hang like a sack of wet grain.
The MB was *not* designed specifically for cradle holds, but can be used that way. Mostly the system was designed for my philosophy of wearing, that is, that the carrier should adapt to you, not the other way around. I can mimic most in-arms holds with a pair of MamaBaby slings.
That said, I can do a lot of the same tricks with an old, nonadjustable Maya Pouch and a maya ring slings with a shoulder redo to the mamababy style (and purple aluminum slingrings...
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For me, the Maya is more a going out of the house sort of carrier, while the mamababy is definitely like the t-shirt of my carrier wardrobe.