There has been claims floating around that Sigg bottles are using plastic lining containing BPA and other poly-vinyls that leach into whatever drink you've put in it. I see also that there is a negative review of them in the product reviews. I wonder where everyone is getting this information from? I cannot find anything to actually validate these claims. I did however find a German study from Stiftung Oekotest (a company that tests for environmental friendliness and health concerns).
The SIGG aluminum bottle they tested received very good ratings: it leaks minimal traces of aluminum at room temperature, more at higher temperatures (that's why you should protect it from heat and not use it with hot drinks as stated in the manual that comes with the bottle), there was no bis-phenol A found, no diethylhexyphthalate, no vinyl. With this it did quite good in the test. They consider traces of aluminum less dangerous than the stuff plastics usually leak.
Germany is generally a lot stricter with it's standards than North America so where is the bad info coming from? Enlighten me please!