negative: if you make it too crowded, the water is boiling over and if you pour too fast, it runs also from the lid - so here you need patience. If I want my teapot filled with hot water completely, I have to turn on 2 cans because the capacity in comparison to standard boilers is quite small.
But if you practice patience when pouring and if in doubt boil water several times, this cooker is really a looker and I would buy it again.