I'm not an umbrella person, especially when I travel. It's just one more thing to carry and, most likely, lose. Since I don't check luggage, an umbrella has never made it into my bag, that is, until I went to Southeast Asia during the rainy season. I had thought that a breathable but rain resistant jacket would be the best way to deal with the drenching rains that I anticipated. But, realizing the humidity would be upwards of 80%, I knew that even the most breathable jacket would turn me into a soggy mess. Hence, the umbrella. I needed one that would be small, sturdy, and able to deal with blasts of winds that I also anticipated. The umbrella that made it into my bag is the REI Travel Umbrella.
What's unique about it -- aside from the hefty price tag -- is that it has a vented canopy. During some heavy downpours with blustery winds in Siem Reap, Cambodia, the umbrella was quite wind resistant: it never turned inside out. But the umbrella is small -- don't even think of squeezing two people under it. I'm pretty petite yet, when I carried a shoulder bag, the umbrella barely kept my torso and bag dry. It's also heavy: weighing in at one pound. The open-close button is relatively smooth, though it opens easier than it closes.
All that being said, I now take this umbrella on any non-hiking trip when I anticipate a lot of rain. I'll be walking the Nantes-Brest Canal in Brittany in a month and will be carrying it on that journey.