If I could just add my tuppennyworth, a few people have noted the advantage of Ti mugs- you can take them from the stove to the lips.
Sorry if I'm missing something here, but if I'm brewing up, when my mug (crusader, stainless, 11 yrs old and still going strong ) boils, the last thing I want to do is put it to my lips. Normally, I pour my water into the plastic mug ( '58, natch ) , and get on with cooking the meal.
When I boil up a brew in the mug, it takes longer for the brew to cool enough to drink than it does for the mug to be cool enough to put to my lips.
Why should the fact that you can't take the can directly off the stove and drink from it be an issue, when I would have thought everyone here would be at least bringing all their water to a boil for hygiene's sake?