If your after a completely leak proof bottle then this isn’t for you, but our son loves these for his milk. Excellent quality, and seal/lid are great. My son ends up biting through the straw after 6 months so buy spares!
After trying a number of different bottles, this is the only one my son would drink from. Design is really cute and it is good quality. Only downside is that it is not spill proof. However no major accidents yet so quite happy with it.