We were happy to see a wide-mouthed, sturdy looking bottle when we opened the Breastflow, and curious to see what that double nipple could do for baby. However, the nipple-in-nipple feature really only seemed to make our feeding experiences more difficult. The large, softer outer nipple collapses very easily. We don't feel that it interfered with milk-flow, but baby's latch would slip a little. Another annoyance? Milk and food got stuck between the two nipples. Now apparently this is expected as they've created built-in "milk-release tabs" that you squeeze to allow the milk to drain back into the bottle. This is just a pain and also felt a little unsanitary.
Had a sturdy feel; comfortable for baby to hold. This bottle has a wide mouth that made filling and cleaning (the base) easy.
No trouble with leaking.
The double nipple and built-in tabs/holes make for extra work while cleaning and assembling.
We just didn't care for the "milk release tabs". Even after squeezing them while tipping, tapping, swishing, etc. we still couldn't get all the milk back in the bottle.