M.L.
I personally do not like metal water bottles. the metals can still leach into the liquid that you are drinking. Also, many metal water bottles have a synthetic lining on the inside that have not so nice chemicals in them, do not just think BPA. their are a lot of other not so nice chemicals that do not get as much press as BPA
I use glass!
these are the best, a little pricey but I have had mine for over a year and a half and it has been well worth the money. Now that I am expecting a baby in May I am also registered for their baby bottles and sippy cups.
http://www.lifefactory.com/