The cup is fairly light but sturdy enough that you can't crush it without putting some real effort into it.
The max size drink for the cup is 16-ounce and there's a notched line in the cup for a 12-ounce "Tall."
There's very little insulation with the plastic and you'll need a cup sleeve to hold a hot cup of coffee.
You can safely microwave liquids in the cup (but remember it will be hot and there's not much in the way of insulation) and clean it in the dishwasher (but only on the top rack).
The cup and lid are both recyclable at the end of their useful lives, but only if you have the proper recycling facilities in your neighborhood.
They also give it a rinse with boiling water each time you bring it in before they serve your drink in it
Overall, I think Starbucks Reusable $1 cup a neat idea and much cheaper than the $9-plus price of their regular tumblers. I think the biggest problem is actually remembering to bring it with you when you go to a Starbucks. Sure, you can leave it in your car, but it might yellow in the sun.