Review (5/5): Work Great. Don't Leak.
I bought these (and a cute little funnel) to take home extra wine from my wine tasting class. Of course, that was before I learned that the course had a rule against taking the wine off campus, so they only got to be used for that purpose once. Sadness.
In any case, they have since been used to take a day's worth of soy milk to work for my coffee. I imagine they'd be great for a large number of tasks. They do not leak (even when on their side in my purse -- thank goodness) and they are relatively sturdy.
Great product. Am very happy with mine.