Nalgene Review

Likes
Nalgenes are known for their durability. An empty Nalgene can survive anything. But fill one with water, and drop it four feet onto rock, and you have an excellent chance of cracking it open. I’ve seen three broken this way. (And it turns out that you can’t send in a broken Nalgene for a free replacement.) All of them were the new formula plastic, which seems to be much brittler than its BPA-containing counterpart. On cold nights, you can fill a Nalgene with hot water and keep it in your sleeping bag. Doing the same with the Klean Kanteen can be dangerous. The plastic does a much better job of insulating liquids.
Because the Nalgene was the dominant water bottle for so long, a number of products were developed to be compatible with the mouth size. Most water filters are sized to fit Nalgene lids, and companies like BCA and Guyot Designs (see http://www.backcountry.com/backcountry-access-nalgene-compatible-stash-hydration-system and http://www.campsaver.com/original-splashguard) design products specifically for the Nalgene. The wide-mouth size has become standard.


Dislikes
The Nalgene comes with just the one attachment device, a loop-top. Because the loop is offset from the bottle itself, it’s much more comfortable to carry clipped to a harness or backpack than the Klean Kanteen. That said, clipping it directly to anything, particularly a climbing harness, is a bad idea with potentially disastrous consequences, because the connection from the lid to the loop is unreliable. This will not matter the vast majority of the time, but a Nalgene will not fit in a standard sized cupholder. Nalgene bottles are not supposed to hold tastes or odors, but our testers discovered that after keeping Gatorade or coffee in a Nalgene overnight the bottle would hold the taste for several days. Testers also discovered that, if not used regularly, the bottle would sour and take on a slight putrid taste and scent, even after cleaning.

Value
The Nalgene is consistently cheaper than the Klean Kanteen. It's more durable and lighter, and an excellent value.

Best Application
Dayhiking/Backpacking: Nalgene. The Klean Kanteen is just too heavy to justify, and the narrow-top version is not compatible with water filters.
Ski touring/Winter Camping: Nalgene. Who doesn’t love a warm Nalgene to cuddle through a cold night? That alone is a selling point – not to mention that most insulating sleeves are designed for Nalgenes.
Climbing: Nalgene. Again, weight is an issue. Just don’t clip it to your harness.

Other Versions
Nalgene makes a huge variety of bottles. The 32oz wide mouth is the one pictured, and the bestselling standard. In production is also the "silo" version, with an identical volume but thinner, designed to be able to fit into backpack pockets or car cupholders. There are two narrow-mouth versions, which are harder to clean and not compatible with filters. Pointless.
Worth considering is the HDPE version, which is the same design as the "classic" version, but lighter and more flexible.