The quality is good and it is interesting that it takes longer to feel the heat from this bottle. I assume this is because the ribbing provides better insulation so the bottle should remain hot for longer, which can only be good. The extra wide opening is excellent too as it makes filling the bottle much easier and safer (no chance of hot water 'blowing' back). I was surprised there was no washer on the bottom of the stopper, like hot water bottles always used to have, but assume this is because the stoppers generally fit better nowadays.