Ah, choices, choices.... I can't answer directly, but have an original model Ultralite in long without the neck thing, and it's a legitimate 20-degree bag so the uprated Ultralite surely is that and perhaps a bit more. I have an FF Swift with down upgrade and optional removable draft collar and it's warmer than the Ultralite. As far as I can tell the Hummingbird is a skinnier Swift equivalent so conceivably could be spec'd to be warmer than the Ultra.

As a coda, Brian Robinsion--he of the first calendar triple crown--used a Hummingbird for most of his hike. It was still in great shape when I looked it over at a talk he gave.

You may be a candidate for the scientific, "eeny, meenie, miney, moe..." method of selection.

Cheers,

Originally Posted By skcreidc
I'm tall, skinny and want a good 20 degree bag under 2 lbs. Western Mountaineering has the Ultralite; lots of good feedback and at 1 lb 15 oz for the tall its under 2 lbs. Feathered Friends has the Hummingbird nano which comes in at 1 lb 11oz for the tall and is minus the neck "thing" to help keep the warmth in. (Hey, some days I have a way with words and some days I no have way.) Anybody here with experience with the Hummingbird nano? For essentially the same price, I would not mind dropping another quarter pound if it seems worth it.
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--Rick