I have a Klean Kanteen I use for when I'm outdoors and I have to say,
the stainless steel is a bit annoying. I have the one that is painted black,
and the black is starting to chip away, leaving specks of paint on my hand
whenever I go to take a drink. I never really mistreated the canteen,
it just naturally happened over time. In hindsight, I probably should have gotten
the Kanteen without the paint, but what the hell.
Another problem is the condensation that forms around the Kanteen;
if you like to keep canteens in your bag, it can be a problem.
Are your issues mentioned regarding the single-walled Kleen Kanteen? I know those are popular because you can boil water in the container and use them more ruggedly outdoors. The stainless would be the way to go with those.
I never had any issues with condensation or chips with my vacuum / double-walled black Kleen Kanteen - although my use-case is different. I keep it in a water bottle pocket holder on backpacks or pouches and try to take good care of them. One of my backpacks has an inner water bottle pocket which I've kept it in and they never sweat or resulted in condensation.