I have used this tumbler for nearly 3 years. It does a fantastic job of keeping ice-cold drinks. The metal straw that came with the tumbler unexpectedly became an item that I use daily! It was loud and made an abrasive noise with the metal interior of this item, so I took it out and now use it frequently with glass or ceramic. I am impressed that the metal straw looks as new as the day I took it out of the box. The brilliant matte finishing of the tumbler does wear off, so take great care when handling this item. I noticed the bottom began to wear down by just placing it on various surfaces after a week, so since then, I have had an extra silicone sleeve protecting it. Any scratch or bump will deteriorate the outer surface of this item to reveal the metal underneath, and that can be seen in the image I provided. I recommend hand-washing this tumbler and cleaning out the metal straw with a pipe cleaner or a brush meant for straws. If any discoloration happens from the inside of the tumbler from various drinks, all you need to do is use a vinegar and warm water solution with a gentle sponge.