Pros:
1. Environmentally sound (refillable, no waste)
2. Longevity/durability
3. Dishwasher safe (sort of)

Cons:
1. Claims of HDPE leaching carcinogens (don't store anything in them long-term)
2. Relatively heavy compared to Nalgene's collapsible canteen product, which is also cheaper.
3. Lids are expendable, go ahead and buy some extras. If they don't fall below the D/W rack and melt, they strike a rock and split, or they just loosen and come off.

Verdict: Perfect for drinking water at the office and for weekend cragging. There are better options for alpine/lightweight applications.

I'll admit. These bottles are kinda a staple for the outdoors. But let me point out a few things that may have gone unnoticed... First of all, why is it that when normally sane people get their hands on a Nalgene, they suddnely become super retarded? I've never seen so many cases of things getting "dropped" from the top of climbs... Are people TRYING to break these things? I've also noticed that people swear by these things. Well, so do I. But not like it's religion. A few of the reviews have mentioned this already, but these things are needlessly heavy. I'd never take one on a long climb or a long approach where weight was a factor. Maybe a trip to the crag, or to work (since I work indoors), but NEVER to, say, a multi-pitch or multi-day outing where I needed to carry a lot of other essential gear. Last time I went out on a long trip, I took a standard gallon apple juice bottle, sans the juice. I reinforced it with duct tape on the bottom and it still weighed less than the Nalgene and held WAY more water. It was just as strong and believe it or not, with a loop of emergence webbing gitrh-hitched around the handle (which was built into the bottle itself), it could be held by a single biner without any fear of the "loop" breaking (a problem I have had with Nalgenes before...). Yes, they're hard to break. Yes, they're good at holding water. Yes, they don't hold flavor that much. And Yes, they're not that expensive. They're "trendy" cool, they are almost a symbol of climbing and the outdoors (like the ice axe or a biner, but more universal...) but are they really worth all the hype they get? I don't really think so. I'll admit that I have one and it gets daily use. I fill it with hot tea, chocolate milk, soup, water, heck, I've even pissed in it before on a cold night to stay warm as I cursed my decision to bivy in the snow... But most of these applications can be performed by a cheap Evian bottle or a gatoraid bottle. Yeah, they're not as durable, but what the F? Do you HAVE to throw your water bottle off the top of the climb? Is it REALLY just too hard to descend with it in the pack or clipped off to a harness (by the way, to people who clip Nalgenes to their harnesses, WHY?) or simply leave it at the bottom of the 45 foot climb and get a drink when you're done? For longer trips or serious multi-pitch, it's simply not worth it in terms of weight. For daily use, it's just fine. It's a great bottle, I just think it gets too much praise that it really hasn't earned... I'd rather use mine at the office and bring a gallon of apple juice for the real stuff.

hosh.

this bottle is all you need, of course unless you need more water.

it froze on a snow trip, and has a lump on the side, but this only means more capacity.

it did get a cracked lid on one camping trip, not snowy, but just general rough terain.. a full sized crack down the threads. Still did not leak a drop.

and to carry one. i suggest the "Bottle Belt". i love it.
plus the bulge holds it fool-proofly.

ok, so I'm an ultralight geek when I feel like it, and have a Nalgene for general uses and abusive uses (like caving), but for significant hikes, climbs, or backpacking trips, gatorade bottles are the key - 1/3 the weight (when empty of course), 1/4 the price, and it comes FULL. They are also no big deal to throw away when they are too gross and if you happen to loose it, no big deal. So, get 1 nalgene if you dont have one, keep your stickers off of it, and get a bunch of gatorade 32 ozers.

Two years ago I went on a day hike with a few friends. We hiked up one side of a rock formation and when coming down the other side it turned into an awkward down climb. I tossed my two hooked together Nalgenes down so my hands would be free. They bounced five or six times before settling about fifty feet under us. I still using those SAME bottles today. Both are in one piece with no cracks.