Bests & Worsts Reviews from Amazon

This was my 2nd generation purchase of a pair of Contigo Mugs from Amazon. The first purchase was based on my satisfaction with a Contigo mug that I won as a door prize at a charity event, and in Jan 2014 I bought the two mugs to replace that one (when I left it in a classroom where I made a presentation - the teacher laughed when I asked if the kids, who know quality when they see it, had by chance returned it to her) - one for my wife and one for me. We used them regularly, and they traveled widely with us, for more than 18 months, but we eventually lost both - at different times. So, in June, I went back to Amazon to replace them. I'm not sure why, but I couldn't find the same pair I'd bought earlier (they seem to be on the site now), so I ended up ordering this pair. They were ~$38, compared to the ~$30 I remembered from the earlier purchase, but I figured that was just inflation.(?) Anyway, these came a couple of months ago, and I was surprised that they were quite different from the earlier ones. The top has a different mechanism, which pops apart for cleaning (not sure, but it seems like an unnecessary improvement, since the previous design worked fine for us) and the overall construction is much lighter weight (thinner walled?). I was surprised to find that I could fill this apparently thin-walled container with hot coffee and never feel any warmth coming through to the outside! It obviously has a very thin, but very efficient, vacuum chamber between the inside and outside - impressive engineering! Until yesterday, when the mug I was carrying in a tote with a bunch of papers LEAKED all over the papers. I checked to make sure that the cover was screwed on tight (it was) and that the button hadn't somehow gotten pressed, but found that the mug still leaked a steady drip when inverted. I was dismayed to find that the other one also leaked when sealed as tightly as possible and held upside down. Though I'd been impressed with the lack of drips from the earlier model, I'm very discouraged with the failure of this new design. It appears that the seal in the new cover design is based on a flimsy flexible plastic gasket that doesn't actually seal very well. (See attached photo) I was surprised while shopping at our local Costco this evening, to see a pair of Contigo mugs very similar to the earlier design discussed above - for only $19.99! I bought them and decided to return the other ones to Amazon - especially because of the price difference. The new ones have a different cover seal design, sort of between the original simple design and the flimsy gasket of the new one from Amazon. I haven't tested them yet, but they look less likely to fail than the more complex ones that did fail. I was disheartened to find that Amazon won't accept return of items like this more than 30 days after delivery, so I'm stuck with them. I apologize for the length of this review, but it's the best way I can see to protest Amazon's product selection, pricing and return policies.