Stainless steel vs. plastic sippy cups, what's the trade-off?

Stainless steel models like the Owala kids tumbler keep drinks cold for hours but cost more, dent if dropped on hard floors, and several r/moderatelygranolamoms threads note paint chipping on certain colors. Plastic options like the Zak Kelso and Munchkin 360 are lighter, cheaper, and easier for small hands, but won't insulate.