I finished my first cup of coffee in the new double-wall glass mug and it was great! No metal or plastic taste tainted the coffee and the silicon top made no adverse affect on it either.
Now to be sure I don't break it!
I'm glad to hear the travel mug is working for you.
Just the fact that it is still in one piece puts you miles ahead of me if it were my mug.
I can only wish you the best of luck in the continued maintenance of the cup in one piece. I know you're really careful with stuff, and are not an uncoordinated clod like me...so I have great hopes for you.