I have never tried glass bottles before, the short bottle and wide opening make it easy to just use your regular sponge or dish rag to clean it. They wash up so clean and clear. No plastic bottle to get hazy or cloudy looking over time. The overall design of the entire nipple seems more natural to the baby. I am sure she can tell it is not skin, so she definitely knows the difference, but in general it is more in proportion to the real thing, especially when looking at how the baby's face goes against the wider area. The glass does not feel fragile. It doesn't feel like the first drop or tap is going to crack or break it. They're a little heavier, it makes a little more tiring for the baby to try and hold it herself too.