Our LO hates being wrapped up. Resisted swaddling with all her little might. We've tried every swaddle and sleep sack we can find and the ergoPouches are the only ones she doesn't actively fight. The shape allows her to move around and feel less constrained while keeping her warm and safe.
We started with the transition one to help with her startle reflex (very helpful that it comes in a 0-3m size!) and once she outgrew it, moved to the standard sacks. They're both awesome!