The first thing you need to know is that stainless metal water bottles aren't for everyone. They have their pros and cons like anything else. On the pro side, they are BPA-free and better for the environment than disposable - or even reusable - plastic water bottles. However, plastic is a much better insulator than steel and aluminum, which means your cold drinks will stay cold and your warm drinks will stay warm for much longer in plastic water bottles than those made from steel. If you are looking for something just for cool drinking water at class or work then a steel water bottle is probably your best option. On long hikes in the hot sun, however, you may want something with better insulation. For hot drinks you're best off with a thermos.

Klean Kanteen water bottles are made from stainless steel, which means there is no need for synthetic liners, which are necessary for aluminum water bottles. The asterisk beside 'dishwasher safe' pertains to the plastic cap, which should not be washed in the dishwasher often. Its holding capacity is somewhere between the Gaiam and SIGG bottles. What we like most about Klean Kanteen are their wide-mouth designs. This makes it easy to insert ice-cubes and to clean out by hand. The price is also between Gaiam and SIGG. As for quality, there really isn't much difference between Klean Kanteen and Gaiam's steel water bottles, although there are more design choices with Klean Kanteen.

SIGG is a very well known Swiss water bottle brand. The asterisk next to small mouth is there to indicate that SIGG does offer wide-mouth designs. However, they were not similar to the other two designs / sizes being compared here so we chose the closest SIGG option, which happens to be small-mouth. Their bottles are made from aluminum, which requires an inner lining. Some of these linings are petroleum or chemical-based, which leads to the same concerns that we have regarding the environmental and health problems for plastic water bottles. The asterisk beside 'secret' lining is there to show that we do not know what the actual ingredients are for their 'patented' liner. However, the SIGG website does go so far as to say that it is 'safe'. Still, I don't like to take chances with my health and if they are not willing to disclose exactly what is in that "secret recipe" then I am not willing to recommend this brand.

Gaiam is a newcomer to the reusable water bottle scene, although they have been a well-known yoga product manufacturer and health lifestyle store for many years. Gaiam offers a quality reusable drinking bottle made from stainless steel. It is just like the Klean Kanteen bottles in everything except variety and the wide-mouth. But if you don't plan on pushing ice-cubes into your bottle regularly, the price (about half) more than makes up for it. The holding capacity is smaller, but we like smaller bottles because they are easier to carry around. It still holds more than those disposable bottles of water you can buy at the store.

There was no clear winner between Klean Kanteen and Gaiam overall. It really all comes down to choice and preference. If you want a wide-mouth bottle and a greater variety of designs to choose from, you would obviously go with Klean Kanteen. If you want to save money while still getting a quality stainless steel water bottle, Gaiam is your best bet.