Alpinelightwrote a review of Hyperlite Mountain Gear 3400 Windrider 55L Backpack on October 27, 2017
Familiarity: I've put it through the wringer
I bought this pack without a whole lot of expectations. Turns out to be the closest thing I've ever found to the old-school do-everything mountain rucksack. The roll-top keeps out rain and snow, as well as the occasional sand-storm. It also has the unexpected benefit of letting it scrunch down into a great day pack, and then expand all the way up to a decent backpacking pack. It's the truest do-anything pack that I've used in a very long time.
You definitely lose convenience from being a top-loader, but for me the simplicity and water resistance make up for it. The external mesh pockets hold more than you'd think, and aren't as delicate as I'd feared. They've put up with some pretty rough treatment and so far so good.
It's not 100% waterproof, since there are two tiny drain holes in the bottom, but I've used it in the rain and things stayed bone dry. Dropped it in the Shaksgam River and nothing got in during that brief dunk. Have used it in the Sierras, Trinity Alps, and most recently a full month in the Chinese Karakoram. So far, so good. I'm totally satisfied.