Super flavor even after several hours, but with drawbacks

I am now for years Soda Stream customer, had the Soda Stream Cool bought 2009 about 1 1/2 years ago the Dynamo and for almost half a year now the Crystal. The water tastes even after hours of beautifully fresh, plastic taste here has no chance.

The whole has for me but two serious disadvantages.
1 disadvantage: the bottleneck thread. I have the bottle about 2-3 months and for daily use can be suddenly the plastic closure is no longer open. Eben had until today. Will I open the bottle and the shutter can not be opened, but I hear broken glass. The next bottle broken.

Have Soda Stream already contacted and received 3 new bottles, but these will suffer sooner or later the same fate. Here in my opinion this is clearly a design flaw. Meanwhile my 4th bottle thus broke down the neck threads, that's just not acceptable.

This leads me without detours to 2. Disadvantage:
The Price.
Real love leads deals, 2 bottles for 16,99 Euro. That the bottles are broken but the thread after 3 months really unacceptable. I can not understand why the glass splintered too.

So unfortunately only 2 star I remain assigned to.